Materials for use in accommodating intraocular lens system

ABSTRACT

There is disclosed an accommodating intraocular lens for implantation in an eye having an optical axis. The lens comprises an anterior portion which in turn comprises an anterior viewing element and an anterior biasing element. The lens further comprises a posterior portion which in turn comprises a posterior viewing element in spaced relationship to the anterior viewing element and a posterior biasing element. The anterior portion and posterior portion meet at first and second apices of the intraocular lens. The anterior portion and the posterior portion and/or the apices are responsive to force thereon to cause the separation between the viewing elements to change. Additional embodiments and methods are also disclosed.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/406,821, filed Apr. 19, 2006, titled MATERIALS FOR USE INACCOMMODATING INTRAOCULAR LENS SYSTEM, which is a continuation of U.S.patent application Ser. No. 10/207,717 (published as U.S. PatentApplication Publication No. 2003/0078657), filed Jul. 25, 2002, titledMATERIALS FOR USE IN ACCOMMODATING INTRAOCULAR LENS SYSTEM, nowabandoned, which is a continuation-in-part of U.S. patent applicationSer. No. 10/020,853, filed Dec. 11, 2001, titled ACCOMMODATINGINTRAOCULAR LENS SYSTEM, now U.S. Pat. No. 7,118,596, which claims thebenefit of U.S. Provisional Patent Application Ser. No. 60/337,343,filed Nov. 9, 2001 and titled ACCOMMODATING INTRAOCULAR LENS SYSTEM;Ser. No. 60/283,856, filed Apr. 13, 2001 and titled ACCOMMODATINGINTRAOCULAR LENS SYSTEM; and Ser. No. 60/264,179, filed Jan. 25, 2001and titled ACCOMMODATING INTRAOCULAR LENS SYSTEM. In addition, theabove-noted application Ser. No. 10/207,717 claims the benefit of U.S.Provisional Patent Application Ser. No. 60/337,343, filed Nov. 9, 2001and titled ACCOMMODATING INTRAOCULAR LENS SYSTEM. The entire disclosureof all of the above-mentioned provisional and nonprovisional patentapplications, and of the above-mentioned publication, is herebyincorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to intraocular lenses and, more particularly, tointraocular lenses that alter the refractive power of the eye inresponse to changes in the tension of the ciliary muscle of the eye.

2. Description of the Related Art

The vast majority of cataract operations involve the implantation of anartificial lens following cataract removal. Typically these lenses havea fixed focal length or, in the case of bifocal or multifocal lenses,have several different fixed focal lengths. Such fixed focal-lengthlenses lack the ability of the natural lens to dynamically change therefractive power of the eye. The various embodiments of the intraocularlens disclosed herein provide an accommodating lens system which altersthe refractive power of the eye in response to changes in tension of theciliary muscle, thereby allowing the lens system to bring into focus onthe retina images of objects that are both near and far from the eye.

SUMMARY OF THE INVENTION

One aspect of the invention is an accommodating intraocular lens forimplantation in an eye having an optical axis. The lens comprises ananterior portion which in turn comprises an anterior viewing elementcomprised of an optic having refractive power and an anterior biasingelement comprising first and second anterior translation membersextending from the anterior viewing element. The lens further comprisesa posterior portion which in turn comprises a posterior viewing elementin spaced relationship to the anterior viewing element and a posteriorbiasing element comprising first and second posterior translationmembers extending from the posterior viewing element. The anteriorportion and posterior portion meet at first and second apices of theintraocular lens such that a plane perpendicular to the optical axis andpassing through the apices is closer to one of said viewing elementsthan to the other of said viewing elements. The anterior portion and theposterior portion are responsive to force thereon to cause theseparation between the viewing elements to change.

Another aspect of the invention is an accommodating intraocular lens forimplantation in an eye having an optical axis. The lens comprises ananterior portion, which in turn comprises an anterior viewing elementcomprised of an optic having refractive power, and an anterior biasingelement comprising first and second anterior translation membersextending from the anterior viewing element. The lens further comprisesa posterior portion which in turn comprises a posterior viewing elementin spaced relationship to the anterior viewing element, and a posteriorbiasing element comprising first and second posterior translationmembers extending from the posterior viewing element. The anteriorportion and posterior portion meet at first and second apices of theintraocular lens. The anterior portion and the posterior portion areresponsive to force thereon to cause the separation between the viewingelements to change. The first anterior translation member forms a firstanterior biasing angle, as the lens is viewed from the side, withrespect to a plane perpendicular to the optical axis and passing throughthe apices. The first posterior translation member forms a firstposterior biasing angle, as the lens is viewed from the side, withrespect to the plane. The first anterior biasing angle and the firstposterior biasing angle are unequal.

Another aspect of the invention is an accommodating intraocular lenscomprising an anterior viewing element comprised of an optic havingrefractive power of less than 55 diopters and a posterior viewingelement comprised of an optic having refractive power. The opticsprovide a combined power of 15-25 diopters and are mounted to moverelative to each other along the optical axis in response to acontractile force by the ciliary muscle of the eye upon the capsular bagof the eye. The relative movement corresponds to change in the combinedpower of the optics of at least one diopter. Alternatively, theaccommodating intraocular lens can further comprise a posterior viewingelement comprised of an optic having a refractive power of zero to minus25 diopters.

A further aspect of the invention is an accommodating intraocular lenscomprising an anterior portion which in turn comprises an anteriorviewing element which has a periphery and is comprised of an optichaving refractive power. The anterior portion further comprises ananterior biasing element comprising first and second anteriortranslation members extending from the anterior viewing element. Thelens further comprises a posterior portion which in turn comprises aposterior viewing element having a periphery, the posterior viewingelement being in spaced relationship to the anterior viewing element,and a posterior biasing element comprising first and second posteriortranslation members extending from the posterior viewing element. Thefirst anterior translation member and the first posterior translationmember meet at a first apex of the intraocular lens, and the secondanterior translation member and the second posterior translation membermeet at a second apex of the intraocular lens, such that force on theanterior portion and the posterior portion causes the separation betweenthe viewing elements to change. Each of the translation members isattached to one of the viewing elements at at least one attachmentlocation. All of the attachment locations are further away from theapices than the peripheries of the viewing elements are from the apices.

A further aspect of the invention is an accommodating intraocular lenscomprising an anterior portion comprised of a viewing element. Theviewing element is comprised of an optic having refractive power. Thelens further comprises a posterior portion comprised of a viewingelement. The viewing elements are mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye. The lens further comprises a distending portioncomprised of a distending member having a fixed end attached to theposterior portion and a free end sized and oriented to distend a portionof the lens capsule such that coupling of forces between the lenscapsule and the intraocular lens is modified by the distending portion.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion comprised of an anterior viewingelement and an anterior biasing element connected to the anteriorviewing element. The anterior viewing element is comprised of an optichaving refractive power. The lens further comprises a posterior portioncomprised of a posterior viewing element and a posterior biasing elementconnected to the posterior viewing element. The lens has an optical axiswhich is adapted to be substantially coincident with the optical axis ofthe eye upon implantation of the lens. The anterior and posteriorviewing elements are mounted to move relative to each other along theoptical axis in response to force generated by the ciliary muscle of theeye. The biasing elements are joined at first and second apices whichare spaced from the optical axis of the lens. The lens further comprisesa distending member extending between the first and second apices.

A further aspect of the invention is an accommodating intraocular lenscomprising an anterior portion comprised of a viewing element. Theviewing element is comprised of an optic having refractive power. Thelens further comprises a posterior portion comprised of a viewingelement. The viewing elements are mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye. The lens further comprises a retention portioncomprised of a retention member having a fixed end attached to theanterior portion and a free end sized and oriented to contact a portionof the lens capsule such that extrusion of the implanted lens throughthe lens capsule opening is inhibited.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion comprised of a viewing element,the viewing element comprised of an optic having refractive power, and aposterior portion comprised of a viewing element. The viewing elementsare mounted to move relative to each other along the optical axis inresponse to force generated by the ciliary muscle of the eye. The lensfurther comprises a distending portion comprised of a distending memberattached to one of the portions, and oriented to distend the lenscapsule such that the distance between a posterior side of the posteriorviewing element and an anterior side of the anterior viewing elementalong the optical axis is less than 3 mm when the ciliary muscle isrelaxed and the lens is in an unaccommodated state.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion comprised of a viewing element,the viewing element comprised of an optic having refractive power, and aposterior portion comprised of a viewing element. The viewing elementsare mounted to move relative to each other along the optical axis inresponse to force generated by the ciliary muscle of the eye. The lensfurther comprises a distending portion comprised of a distending memberattached to one of the portions, and oriented to distend the lenscapsule. The distending causes the lens capsule to act on at least oneof the posterior and anterior portions such that separation between theviewing elements is reduced when the ciliary muscle is relaxed and thelens is in an unaccommodated state.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion comprised of a viewing element,the viewing element comprised of an optic having refractive power, and aposterior portion comprised of a viewing element. The viewing elementsare mounted to move relative to each other along the optical axis inresponse to force generated by the ciliary muscle of the eye. The lensfurther comprises a distending member attached to the posterior portion.The distending member is separate from the biasing members and reshapesthe lens capsule such that force coupling between the ciliary muscle andthe lens is modified to provide greater relative movement between theviewing elements when the lens moves between an unaccommodated state andan accommodated state in response to the ciliary muscle.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion comprised of an anterior viewingelement and an anterior biasing element connected to the anteriorviewing element, the anterior viewing element being comprised of anoptic having refractive power. The lens further comprises a posteriorportion comprised of a posterior viewing element and a posterior biasingelement connected to the posterior viewing element. The lens has anoptical axis which is adapted to be substantially coincident with theoptical axis of the eye upon implantation of the lens. The anterior andposterior viewing elements are mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye. The biasing elements are joined at first and secondapices which are spaced from the optical axis of the lens. The lensfurther comprises first and second distending members. Each of themembers is attached to one of the anterior and posterior portions andextends away from the optical axis. The first member is disposed betweenthe apices on one side of the intraocular lens and the second member isdisposed between the apices on the opposite side of the intraocularlens. The distending members are oriented to distend portions of thelens capsule such that the viewing elements are relatively movablethrough a range of at least 1.0 mm in response to contraction of theciliary muscle.

A further aspect of the invention is an accommodating intraocular lenscomprising an anterior portion which is in turn comprised of a viewingelement. The anterior viewing element is comprised of an optic having adiameter of approximately 3 mm or less and a refractive power of lessthan 55 diopters. The lens further comprises a posterior portioncomprised of a viewing element. The viewing elements are mounted to moverelative to each other along the optical axis in response to forcegenerated by the ciliary muscle of the eye. The lens further comprises adistending portion comprised of a distending member having a fixed endattached to the posterior portion and a free end sized and oriented todistend a portion of the lens capsule such that coupling of forcesbetween the lens capsule and the intraocular lens is increased.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion comprised of a viewing element,the anterior viewing element being comprised of an optic having arefractive portion with a refractive power of less than 55 diopters. Thelens further comprises a posterior portion comprised of a viewingelement. The lens has an optical axis which is adapted to besubstantially coincident with the optical axis of the eye uponimplantation of the lens. The posterior viewing element comprises anoptic arranged substantially coaxially with the anterior optic on theoptical axis of the lens. The posterior optic has a larger diameter thanthe refractive portion of the anterior optic. The posterior opticcomprises a peripheral portion having positive refractive power andextending radially away from the optical axis of the lens beyond theperiphery of the refractive portion of the anterior optic, so that atleast a portion of the light rays incident upon the posterior optic canbypass the refractive portion of the anterior optic.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion comprised of a viewing element,the anterior viewing element being comprised of an optic having arefractive power of less than 55 diopters. The lens further comprises aposterior portion comprised of a viewing element. The lens has anoptical axis which is adapted to be substantially coincident with theoptical axis of the eye upon implantation of the lens. The posteriorviewing element comprises an optic arranged substantially coaxially withthe anterior optic on the optical axis of the lens. The posterior optichas a larger diameter than the anterior optic. The posterior opticcomprises a peripheral portion having positive refractive power andextending radially away from the optical axis of the lens beyond theperiphery of the anterior optic, so that at least a portion of the lightrays incident upon the posterior optic can bypass the anterior optic.

A further aspect of the invention is an intraocular lens. The lenscomprises an optic and a pair of elongate members extending from theoptic. The members are comprised of a shape memory alloy.

A further aspect of the invention is an accommodating intraocular lensfor implantation in an eye having an optical axis and a lens capsulehaving a capsule opening for receiving the lens. The lens comprises aposterior portion comprised of a posterior viewing element, and ananterior portion comprised of an anterior viewing element. The anteriorviewing element is comprised of an optic having refractive power. Theviewing elements are mounted to move relative to each other along theoptical axis in response to force generated by the ciliary muscle of theeye. The anterior portion is adapted to contact portions of the lenscapsule while being spaced from the lens capsule in at least onelocation so as to provide a fluid flow channel that extends from aregion between the viewing elements to a region outside the capsule.

A further aspect of the invention is an accommodating intraocular lens.The lens comprises an anterior portion which in turn comprises ananterior viewing element having a periphery and comprised of an optichaving refractive power, and an anterior biasing element comprising atleast one anterior translation member attached to a first attachmentarea on the periphery of the anterior viewing element. The firstattachment area has a thickness in a direction substantiallyperpendicular to the periphery and a width in a direction substantiallyparallel to the periphery. The ratio of the width to the thickness isequal to or greater than 3.

A further aspect of the invention is a method of manufacturing anintraocular lens having anterior and posterior viewing elements arrangedalong a common optical axis. The method comprises defining an anteriorviewing element mold space and a posterior viewing element mold space,arranging the anterior viewing element mold space and the posteriorviewing element mold space along a mold axis substantially coincidentwith the optical axis of the lens, and molding the anterior viewingelement in the anterior viewing element mold space while the anteriorviewing element mold space and the posterior viewing element mold spaceare arranged substantially along the mold axis.

A further aspect of the invention is a method of preparing anaccommodating intraocular lens having an optical axis for subsequentimplantation. The method comprises providing an intraocular lens havingfirst and second viewing elements interconnected by plural members. Atleast a portion of the members are disposed from the optical axis by adistance greater than a periphery of at least one of the viewingelements. This distance is measured orthogonal to the optical axis. Themethod further comprises drawing the members inwardly toward the opticalaxis by relatively rotating the first and second viewing elements. Inone variation of the method, the first and second viewing elements arerelatively rotated about the optical axis.

A further aspect of the invention is an accommodating intraocular lens,which comprises an anterior portion having an anterior viewing element,and a posterior portion having a posterior viewing element. The viewingelements are positioned to move relative to each other along an opticalaxis in response to action of the ciliary muscle of the eye. Theanterior and posterior portions comprise a single piece of material.

A further aspect of the invention is an accommodating intraocular lens,which comprises first and second optics. At least one of the optics hasrefractive power. The optics are mounted by an articulated frame to moverelative to each other along an optical axis in response to action of aciliary muscle. The frame is formed of a single piece of material. Inone variation of the lens, at least one of the optics is formed of amaterial which is different from the material of the frame.

A further aspect of the invention is an accommodating intraocular lens,which comprises an anterior portion having an anterior viewing elementcomprising an optic having refractive power. The lens further comprisesa posterior portion having a posterior viewing element. The viewingelements are positioned to move relative to each other along an opticalaxis in response to action of the ciliary muscle of the eye. At leastone of the anterior and posterior portions has at least one separationmember with a contact surface. The at least one separation member isconfigured to prevent contact between the anterior viewing element andthe posterior viewing element by inhibiting relative movement of theanterior and posterior portions toward each other beyond a minimumseparation distance. The contact surface contacts an opposing surface ofthe intraocular lens over a contact area when the portions are at theminimum separation distance. At least one of the surfaces has anadhesive affinity for the other of the surfaces. The contact area issufficiently small to prevent adhesion between the surfaces when theanterior portion and the posterior portion are separated by the minimumseparation distance. In one variation of the lens, the contact surfaceand the opposing surface are comprised of the same material.

A further aspect of the invention is an intraocular lens, whichcomprises first and second interconnected viewing elements mounted tomove relative to each other along an optical axis in response to actionof a ciliary muscle. At least one of the viewing elements includes anoptic having refractive power. The lens is formed by the process ofproviding a first outer mold and a second outer mold, and an inner moldtherebetween. The first outer mold and the inner mold define a firstmold space, and the second outer mold and the inner mold define a secondmold space. The process further comprises molding the viewing elementsand the optic as a single piece by filling the first and second moldspaces with a material, such that the first viewing element is formed inthe first mold space and the second viewing element is formed in thesecond mold space. The process further comprises removing the first andsecond outer molds from the lens while the inner mold remains betweenthe viewing elements, and removing the inner mold from between theviewing elements while the viewing elements remain interconnected.

A further aspect of the invention is a method of making an intraocularlens having first and second interconnected viewing elements wherein atleast one of the viewing elements includes an optic having refractivepower. The method comprises providing a first outer mold and a secondouter mold, and an inner mold therebetween. The first outer mold and theinner mold define a first mold space, and the second outer mold and theinner mold define a second mold space. The process further comprisesmolding the viewing elements and the optic as a single piece by fillingthe first and second mold spaces with a material, such that the firstviewing element is formed in the first mold space and the second viewingelement is formed in the second mold space. The process furthercomprises removing the first and second outer molds from the lens whilethe inner mold remains between the viewing elements, and removing theinner mold from between the viewing elements while the viewing elementsremain interconnected. In one variation, providing the inner mold maycomprise molding the inner mold. In another variation, the inner moldhas a first inner mold face and a second inner mold face opposite thefirst inner mold face, and providing the inner mold comprises machiningthe inner mold, which in turn comprises machining the first inner moldface and the second inner mold face in a single piece of material.

A further aspect of the invention is an accommodating intraocular lens,which comprises first and second optics. At least one of the optics hasrefractive power. The optics are mounted to move relative to each otheralong an optical axis in response to action of a ciliary muscle. Thefirst optic is formed of a first polymer having a number of recurringunits including first-polymer primary recurring units, and the secondoptic is formed of a second polymer having a number of recurring unitsincluding second-polymer primary recurring units. No more than about 10mole percent of the recurring units of the first polymer are the same asthe second-polymer primary recurring units and no more than about 10mole percent of the recurring units of the second polymer are the sameas the first-polymer primary recurring units. In one variation, thefirst optic may comprise an anterior optic, the second optic maycomprise a posterior optic, the first polymer may comprise silicone, andthe second polymer may comprise acrylic. In another variation, the firstoptic may comprise an anterior optic, the second optic may comprise aposterior optic, the first polymer may comprise high-refractive-indexsilicone, and the second polymer may comprise hydrophobic acrylic.

All of these aspects are intended to be within the scope of theinvention herein disclosed. These and other aspects of the inventionwill become readily apparent to those skilled in the art from thefollowing detailed description of the preferred embodiments havingreference to the attached figures, the invention not being limited toany particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus summarized the general nature of the invention, certainpreferred embodiments and modifications thereof will become apparent tothose skilled in the art from the detailed description herein havingreference to the figures that follow, of which:

FIG. 1 is a sectional view of the human eye, with the lens in theunaccommodated state.

FIG. 2 is a sectional view of the human eye, with the lens in theaccommodated state.

FIG. 3 is a perspective view of one embodiment of an intraocular lenssystem.

FIG. 4 is a side view of the lens system.

FIG. 5 is a rear perspective view of the lens system.

FIG. 6 is a front view of the lens system.

FIG. 7 is a rear view of the lens system.

FIG. 8 is a top view of the lens system.

FIG. 9 is a side sectional view of the lens system.

FIG. 10 is a top sectional view of the lens system.

FIG. 11 is a second perspective view of the lens system.

FIG. 12 is a third perspective view of the lens system.

FIG. 13 is a side view of the lens system in the unaccommodated state.

FIG. 14 is a side sectional view of the lens system in theunaccommodated state.

FIG. 15 is a top sectional view of the lens system in the unaccommodatedstate.

FIG. 16 is a sectional view of the human eye with the lens systemimplanted in the capsular bag and the lens system in the accommodatedstate.

FIG. 17 is a sectional view of the human eye with the lens systemimplanted in the capsular bag and the lens system in the unaccommodatedstate.

FIG. 17A is a sectional view of an arm of the lens system.

FIG. 17B is a sectional view of another embodiment of the arm of thelens system.

FIGS. 17C-17L are sectional views of other embodiments of the arm of thelens system.

FIG. 17M is a side sectional view of another embodiment of the lenssystem.

FIG. 17N is a side sectional view of another embodiment of the lenssystem.

FIG. 18 is a side view of another embodiment of the lens system.

FIG. 19 is a side sectional view of another embodiment of the lenssystem.

FIG. 20 is a rear perspective view of another embodiment of the lenssystem.

FIG. 21 is a partial top sectional view of another embodiment of thelens system, implanted in the capsular bag.

FIG. 21A is a front view of another embodiment of the lens system.

FIG. 21B is a front view of another embodiment of the lens system.

FIG. 21C is a front view of another embodiment of the lens system.

FIG. 22 is a partial side sectional view of another embodiment of thelens system, implanted in the capsular bag.

FIG. 22A is a side view of a stop member system employed in oneembodiment of the lens system.

FIG. 23 is a side view of a mold system for forming the lens system.

FIG. 24 is a side sectional view of the mold system.

FIG. 25 is a perspective view of a first mold portion.

FIG. 26 is a perspective view of a second mold portion.

FIG. 27 is a top view of the second mold portion.

FIG. 28 is a side sectional view of the second mold portion.

FIG. 29 is another side sectional view of the second mold portion.

FIG. 30 is a bottom view of a center mold portion.

FIG. 31 is a top view of the center mold portion.

FIG. 32 is a sectional view of the center mold portion.

FIG. 33 is another sectional view of the center mold portion.

FIG. 34 is a perspective view of the center mold portion.

FIG. 34A is a partial cross sectional view of an apex of the lenssystem, showing a set of expansion grooves formed therein.

FIG. 35 is a schematic view of another embodiment of the lens system.

FIG. 36 is a schematic view of another embodiment of the lens system.

FIG. 37 is a perspective view of another embodiment of the lens system.

FIG. 38 is a top view of another embodiment of the lens system.

FIG. 38A is a schematic view of another embodiment of the lens system,as implanted in the capsular bag.

FIG. 38B is a schematic view of the embodiment of FIG. 38A, in theaccommodated state.

FIG. 38C is a schematic view of biasers installed in the lens system.

FIG. 38D is a schematic view of another type of biasers installed in thelens system.

FIG. 38E is a perspective view of another embodiment of the lens system.

FIGS. 39A-39B are a series of schematic views of an insertion techniquefor use in connection with the lens system

FIG. 40 is a schematic view of fluid-flow openings formed in theanterior aspect of the capsular bag.

FIG. 40A is a front view of the lens system, illustrating one stage of afolding technique for use with the lens system.

FIG. 40B is a front view of the lens system, illustrating another stageof the folding technique.

FIG. 40C illustrates another stage of the folding technique.

FIG. 40D illustrates another stage of the folding technique.

FIG. 40E illustrates another stage of the folding technique.

FIG. 40F illustrates another stage of the folding technique.

FIG. 40G is a perspective view of a folding tool for use with the lenssystem.

FIG. 41 is a sectional view of an aspheric optic for use with the lenssystem.

FIG. 42 is a sectional view of an optic having a diffractive surface foruse with the lens system.

FIG. 43 is a sectional view of a low-index optic for use with the lenssystem.

FIG. 44 is a side elevation view of another embodiment of the lenssystem with a number of separation members.

FIG. 45 is a front elevation view of the lens system of FIG. 44.

FIG. 46 is an overhead sectional view of the lens system of FIG. 44.

FIG. 47 is an overhead sectional view of the lens system of FIG. 44,with the viewing elements at a minimum separation distance.

FIG. 48 is a closeup view of the contact between a separation member andan opposing surface.

FIG. 49 is a side sectional view of an apparatus and method formanufacturing a center mold.

FIG. 50 is another side sectional view of the apparatus and method ofFIG. 49.

FIG. 51 is another side sectional view of the apparatus and method ofFIG. 49.

FIG. 52 is another side sectional view of the apparatus and method ofFIG. 49.

FIG. 53 is another side sectional view of the apparatus and method ofFIG. 49.

FIG. 54 is a side sectional view of the lens system in position on thecenter mold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT I. The Human Eye andAccommodation

FIGS. 1 and 2 show the human eye 50 in section. Of particular relevanceto the present disclosure are the cornea 52, the iris 54 and the lens56, which is situated within the elastic, membranous capsular bag orlens capsule 58. The capsular bag 58 is surrounded by and suspendedwithin the ciliary muscle 60 by ligament-like structures called zonules62.

As light enters the eye 50, the cornea 52 and the lens 56 cooperate tofocus the incoming light and form an image on the retina 64 at the rearof the eye, thus facilitating vision. In the process known asaccommodation, the shape of the lens 56 is altered (and its refractiveproperties thereby adjusted) to allow the eye 50 to focus on objects atvarying distances. A typical healthy eye has sufficient accommodation toenable focused vision of objects ranging in distance from infinity(generally defined as over 20 feet from the eye) to very near (closerthan 10 inches).

The lens 56 has a natural elasticity, and in its relaxed state assumes ashape that in cross-section resembles a football. Accommodation occurswhen the ciliary muscle 60 moves the lens from its relaxed or“unaccommodated” state (shown in FIG. 1) to a contracted or“accommodated” state (shown in FIG. 2). Movement of the ciliary muscle60 to the relaxed/unaccommodated state increases tension in the zonules62 and capsular bag 58, which in turn causes the lens 56 to take on athinner (as measured along the optical axis) or taller shape as shown inFIG. 1. In contrast, when the ciliary muscle 60 is in thecontracted/accommodated state, tension in the zonules 62 and capsularbag 58 is decreased and the lens 56 takes on the fatter or shorter shapeshown in FIG. 2. When the ciliary muscles 60 contract and the capsularbag 58 and zonules 62 slacken, some degree of tension is maintained inthe capsular bag 58 and zonules 62.

II. The Lens System: Structure

FIGS. 3-17 depict one embodiment of an intraocular lens system 100 whichis configured for implantation into the capsular bag 58 in place of thenatural lens 56, and is further configured to change the refractiveproperties of the eye in response to the eye's natural process ofaccommodation. With reference to FIG. 3, a set of axes is included toillustrate the sense of directional terminology which will be usedherein to describe various features of the lens system 100. The terms“anterior” and “posterior” refer to the depicted directions on theoptical axis of the lens 100 shown in FIG. 3. When the lens 100 isimplanted in an eye, the anterior direction extends toward the corneaand the posterior direction extends toward the retina, with the opticalaxis of the lens substantially coincident with the optical axis of theeye shown in FIGS. 1 and 2. The terms “left” and “right” refer to thedirections shown on the lateral axis, which is orthogonal to the opticalaxis. In addition, the terms “upper” and “lower” refer to the directionsdepicted on the transverse axis which is orthogonal to both of theoptical axis and the lateral axis.

This system of axes is depicted purely to facilitate description herein;thus, it is not intended to limit the possible orientations which thelens system 100 may assume during use. For example, the lens system 100may rotate about, or may be displaced along, the optical axis during usewithout detracting from the performance of the lens. It is clear that,should the lens system 100 be so rotated about the optical axis, thetransverse axis may no longer have an upper-lower orientation and thelateral axis may no longer have a left-right orientation, but the lenssystem 100 will continue to function as it would when oriented asdepicted in FIG. 3. Accordingly, when the terms “upper,” “lower,” “left”or “right” are used in describing features of the lens system 100, suchuse should not be understood to require the described feature to occupythe indicated position at any or all times during use of the lens system100. Similarly, such use should not be understood to require the lenssystem 100 to maintain the indicated orientation at any or all timesduring use.

As best seen in FIG. 4, the lens system 100 has an anterior portion 102which is anterior or forward of the line A-A (which represents a planesubstantially orthogonal to the optical axis and intersecting first andsecond apices 112, 116) and a posterior portion 104 which is posterioror rearward of the line A-A. The anterior portion 102 comprises ananterior viewing element 106 and an anterior biasing element 108. Theanterior biasing element 108 in turn comprises a first anteriortranslation member 110 which extends from the anterior viewing element106 to the first apex 112 and a second anterior translation member 114which extends from the anterior viewing element 106 to the second apex116. In the illustrated embodiment the first anterior translation member110 comprises a right arm 110 a and a left arm 110 b (see FIG. 3). Inaddition, the depicted second anterior translation member 114 comprisesa right arm 114 a and a left arm 114 b. However, in other embodimentseither or both of the first and second anterior translation members 110,114 may comprise a single arm or member, or more than two arms ormembers.

As best seen in FIGS. 4, 5 and 7, the posterior portion 104 includes aposterior viewing element 118 and a posterior biasing element 120. Theposterior biasing element 120 includes a first posterior translationmember 122 extending from the posterior viewing element 118 to the firstapex 112 and a second posterior translation member 124 extending fromthe posterior viewing element 118 to the second apex 116. In theillustrated embodiment, the first posterior translation member comprisesa right arm 122 a and a left arm 122 b. Likewise, the depicted secondposterior translation member 124 comprises a right arm 124 a and a leftarm 124 b. However, in other embodiments either or both of the first andsecond posterior translation members 122, 124 may comprise a single armor member, or more than two arms or members.

In the embodiment shown in FIG. 4, the anterior biasing element 108 andthe posterior biasing element are configured symmetrically with respectto the plane A-A as the lens system 100 is viewed from the side. As usedherein to describe the biasing elements 108, 120, “symmetric” or“symmetrically” means that, as the lens system 100 is viewed from theside, the first anterior translation member 110 and the first posteriortranslation member 122 extend from the first apex 112 at substantiallyequal first anterior and posterior biasing angles θ₁, θ₂ with respect tothe line A-A (which, again, represents the edge of a plane which issubstantially orthogonal to the optical axis and intersects the firstand second apices 112, 116) and/or that the second anterior translationmember 114 and the second posterior translation member 124 extend fromthe second apex 116 at substantially equal second anterior and posteriorbiasing angles θ₃, θ₄ with respect to the line A-A. Alternative orasymmetric configurations of the biasing elements are possible, as willbe discussed in further detail below. It should be further noted that asymmetric configuration of the biasing elements 108, 120 does notdictate symmetric positioning of the viewing elements with respect tothe line A-A; in the embodiment shown in FIG. 4 the anterior viewingelement 106 is closer to the line A-A than is the posterior viewingelement.

Preferably, both the anterior viewing element 106 and the posteriorviewing element 118 comprise an optic or lens having refractive power.(As used herein, the term “refractive” or “refractive power” shallinclude “diffractive” or “diffractive power”.) The preferred powerranges for the optics are discussed in detail below. In alternativeembodiments one or both of the anterior and posterior viewing elements106, 118 may comprise an optic with a surrounding or partiallysurrounding perimeter frame member or members, with some or all of thebiasing elements/translation members attached to the frame member(s). Asa further alternative, one of the viewing elements 106, 118 may comprisea perimeter frame with an open/empty central portion or void located onthe optical axis (see FIG. 20 and discussion below), or a perimeterframe member or members with a zero-power lens or transparent membertherein. In still further variations, one of the viewing elements 106,118 may comprise only a zero-power lens or transparent member.

In a presently preferred embodiment, a retention portion 126 is coupledto the anterior portion 102, preferably at the anterior viewing element106. The retention portion 126 preferably includes a first retentionmember 128 and a second retention member 130, although in alternativeembodiments the retention portion 126 may be omitted altogether, or maycomprise only one retention member or more than two retention members.The first retention member 128 is coupled to the anterior viewingelement 106 at a fixed end 128 a and also includes a free end 128 bopposite the fixed end 128 a. Likewise, the second retention member 130includes a fixed end 130 a and a free end 130 b. The retention members128, 130 are illustrated as being coupled to the anterior viewingelement 106 at the upper and lower edges thereof; however, the retentionmembers 128, 130 may alternatively be attached to the anterior viewingelement 106 at other suitable edge locations.

In the preferred embodiment, the posterior portion 104 includes adistending portion 132, preferably attached to the posterior viewingelement 118. The preferred distending portion 132 includes a firstdistending member 134 which in turn includes a fixed end 134 a, a freeend 134 b opposite the fixed end 134 a and preferably also includes anopening 134 c formed therein. The preferred distending portion 132 alsocomprises a second distending member 136 with a fixed end 136 a, a freeend 136 b and preferably an opening 136 c formed therein. In alternativeembodiments, the distending portion 132 may be omitted altogether, ormay comprise a single distending member or more than two distendingmembers. To optimize their effectiveness, the preferred location for thedistending members 134, 136 is 90 degrees away (about the optical axis)from the apices 112, 116 on the posterior portion 104. Where the biasingelements form more than two apices (or where two apices are not spaced180 degrees apart about the optical axis), one or more distendingmembers may be positioned angularly midway between the apices about theoptical axis. Alternatively, the distending member(s) may occupy othersuitable positions relative to the apices (besides the “angularlymidway” positions disclosed above); as further alternatives, thedistending member(s) may be located on the anterior portion 102 of thelens system 100, or even on the apices themselves. The functions of theretention portion 126 and the distending portion 132 will be describedin greater detail below.

III. The Lens System: Function/Optics

The anterior and posterior biasing elements 108, 120 function in aspringlike manner to permit the anterior viewing element 106 andposterior viewing element 118 to move relative to each other generallyalong the optical axis. The biasing elements 108, 120 bias the viewingelements 106, 118 apart so that the elements 106, 108 separate to theaccommodated position or accommodated state shown in FIG. 4. Thus, inthe absence of any external forces, the viewing elements are at theirmaximum separation along the optical axis. The viewing elements 106, 118of the lens system 100 may be moved toward each other, in response to aciliary muscle force of up to 2 grams, to provide an unaccommodatedposition by applying appropriate forces upon the anterior and posteriorportions 102, 104 and/or the apices 112, 116.

When the lens system 100 is implanted in the capsular bag 58 (FIGS.16-17) the above described biasing forces cause the lens system 100 toexpand along the optical axis so as to interact with both the posteriorand anterior aspects of the capsular bag. Such interaction occursthroughout the entire range of motion of the ciliary muscle 60. At oneextreme the ciliary muscle is relaxed and the zonules 62 pull thecapsular bag 58 radially so as to cause the bag to become more diskshaped. The anterior and posterior sides of the bag, in turn, applyforce to the anterior and posterior portions 102, 104 of the lens system100, thereby forcing the viewing elements 106, 118 toward each otherinto the accommodated position. At the other extreme, the ciliary musclecontracts and the zonules 62 move inwardly to provide slack in thecapsular bag 58 and allow the bag to become more football-shaped. Theslack in the bag is taken up by the lens system due to the biasing-apartof the anterior and posterior viewing elements 106, 118. As the radialtension in the bag is reduced, the viewing elements 106, 118 move awayfrom each other into an accommodated position. Thus, the distancebetween the viewing elements 106, 118 depends on the degree ofcontraction or relaxation of the ciliary muscle 60. As the distancebetween the anterior and posterior viewing elements 106, 118 is varied,the focal length of the lens system 100 changes accordingly. Thus, whenthe lens system 100 is implanted into the capsular bag (see FIGS. 16-17)the lens system 100 operates in conjunction with the naturalaccommodation processes of the eye to move between the accommodated(FIG. 16) and unaccommodated (FIG. 17) states in the same manner aswould a healthy “natural” lens. Preferably, the lens system 100 can movebetween the accommodated and unaccommodated states in less than aboutone second.

The entire lens system 100, other than the optic(s), thus comprises anarticulated frame whose functions include holding the optic(s) inposition within the capsular bag and guiding and causing movement of theoptic(s) between the accommodated and unaccommodated positions.

Advantageously, the entire lens system 100 may comprise a single pieceof material, i.e. one that is formed without need to assemble two ormore components by gluing, heat bonding, the use of fasteners orinterlocking elements, etc. This characteristic increases thereliability of the lens system 100 by improving its resistance tomaterial fatigue effects which can arise as the lens system experiencesmillions of accommodation cycles throughout its service life. It will bereadily appreciated that the molding process and mold tooling discussedherein, lend themselves to the molding of lens systems 100 that comprisea single piece of material. However, any other suitable technique may beemployed to manufacture single-piece lens systems.

In those embodiments where the optic(s) are installed into annular orother perimeter frame member(s) (see discussion below), the articulatedframe may comprise a single piece of material, to obtain the performanceadvantages discussed above. It is believed that the assembly of theoptic(s) to the articulated frame will not substantially detract fromthe achievement of these advantages.

The lens system 100 has sufficient dynamic range that the anterior andposterior viewing elements 106, 118 move about 0.5-4 mm, preferablyabout 1-3 mm, more preferably about 1-2 mm, and most preferably about1.5 mm closer together when the lens system 100 moves from theaccommodated state to the unaccommodated state. In other words theseparation distance X (see FIGS. 9-10, 14-15) between the anterior andposterior viewing elements 106, 118, which distance may for presentpurposes be defined as the distance along the optical axis (or aparallel axis) between a point of axial intersection with the posteriorface of the anterior viewing element 106 and a point of axialintersection with the anterior face of the posterior viewing element118, decreases by the amount(s) disclosed above upon movement of thelens system 100 to the unaccommodated state. Simultaneously, in thepreferred mode the total system thickness Y decreases from about 3.0-4.0mm in the accommodated state to about 1.5-2.5 mm in the unaccommodatedstate.

As may be best seen in FIG. 6, the first anterior translation member 110connects to the anterior viewing element 106 via connection of the leftand right arms 110 a, 110 b to first and second transition members 138,140 at attachment locations 142, 144. The second anterior translationmember 114 connects to the anterior viewing element 106 via connectionof left and right arms 114 a, 114 b to the first and second transitionmembers 138, 140 at attachment locations 146, 148. This is a presentlypreferred arrangement for the first and second anterior translationmembers 110, 114; alternatively, the first and second anteriortranslation members 110, 114 could be connected directly to the anteriorviewing element 106, as is the case with the connection of the first andsecond posterior translation members 122, 124 to the posterior viewingelement 118.

However the connection is established between the first and secondanterior translation members 110, 114 and the anterior viewing element106, it is preferred that the attachment locations 142, 144corresponding to the first anterior translation member 110 be fartheraway from the first apex 112 than is the closest edge or the peripheryof the anterior viewing element 106. This configuration increases theeffective length of the first anterior translation member 110/arms 110a, 110 b, in comparison to a direct or straight attachment between theapex 112 and the nearest/top edge of the anterior viewing element 106.For the same reasons, it is preferred that the attachment locations 146,148 associated with the second anterior translation member 114 befarther away from the second apex 116 than is the closest/bottom edge ofthe anterior viewing element 106.

As best seen in FIG. 7, the first posterior translation member 122 ispreferably connected directly to the posterior viewing element 118 viaattachment of the left and right arms 122 a, 122 b to the element 118 atattachment points 150, 152. Likewise, the second posterior translationmember 124 is preferably directly connected to the posterior viewingelement 118 via connection of the left and right arms 124 a, 124 b tothe element 118 at attachment points 154, 156, respectively. Inalternative embodiments, the first and second posterior translationmembers 124, 122 can be connected to the posterior viewing element viaintervening members as is done with the anterior viewing element 106. Nomatter how these connections are made, it is preferred that theattachment locations 150, 152 be spaced further away from the first apex112 than is the nearest edge or the periphery of the posterior viewingelement 118. Similarly, it is preferred that the attachment locations154, 156 be spaced further away from the second apex 116 than is theclosest edge of the posterior viewing element 118.

By increasing the effective length of some or all of the translationmembers 110, 114, 122, 124 (and that of the arms 110 a, 110 b, 114 a,114 b, 122 a, 122 b, 124 a, 124 b where such structure is employed), thepreferred configuration of the attachment locations 142, 144, 146, 148,150, 152, 154, 156 relative to the first and second apices 112, 116enables the anterior and/or posterior viewing elements 106, 118 to movewith respect to one another a greater distance along the optical axis,for a given angular displacement of the anterior and/or posteriortranslation members. This arrangement thus facilitates a more responsivespring system for the lens system 100 and minimizes material fatigueeffects associated with prolonged exposure to repeated flexing.

In the illustrated embodiment, the attachment location 142 of the firstanterior translation member 110 is spaced from the correspondingattachment location 146 of the second anterior translation member 114along the periphery of the anterior viewing element, and the samerelationship exists between the other pairs of attachment locations 144,148; 150, 154; and 152, 156. This arrangement advantageously broadensthe support base for the anterior and posterior viewing elements 106,118 and prevents them from twisting about an axis parallel to thelateral axis, as the viewing elements move between the accommodated andunaccommodated positions.

It is also preferred that the attachment locations 142, 144 of the firstanterior translation member 110 be located equidistant from the firstapex 112, and that the right and left arms 110 a, 110 b of the member110 be equal in length. Furthermore, the arrangement of the attachmentlocations 146, 148, arms 114 a, 114 b and second apex preferably mirrorsthat recited above regarding the first anterior translation member 110,while the apices 112, 116 are preferably equidistant from the opticalaxis and are situated 180 degrees apart. This configuration maintainsthe anterior viewing element 106 orthogonal to the optical axis as theviewing element 106 moves back and forth and the anterior viewingelement flexes.

For the same reasons, a like combination of equidistance and equallength is preferred for the first and second posterior translationmembers 122, 124 and their constituent arms 122 a, 122 b, 124 a, 124 band attachment points 150, 152, 154, 156, with respect to the apices112, 116. However, as shown the arms 122 a, 122 b, 124 a, 124 b need notbe equal in length to their counterparts 110 a, 110 b, 114 a, 114 b inthe first and second anterior translation members 110, 114.

Where any member or element connects to the periphery of the anterior orposterior viewing elements 106, 118, the member defines a connectiongeometry or attachment area with a connection width W and a connectionthickness T (see FIG. 4 and the example illustrated therein, of theconnection of the second posterior translation member 124 to theposterior viewing element 118). For purposes of clarity, the connectionwidth is defined as being measured along a direction substantiallyparallel to the periphery of the viewing element in question, and theconnection thickness is defined as measured along a directionsubstantially perpendicular to the periphery of the viewing element.(The periphery itself is deemed to be oriented generally perpendicularto the optical axis as shown in FIG. 4.) Preferably, no attachment areaemployed in the lens system 100 has a ratio of width to thickness lessthan 3. It has been found that such a geometry reduces distortion of theviewing element/optic due to localized forces. For the same reasons, itis also preferred that each of the translation members 110, 114, 122,124 be connected to the periphery of the respective viewing elements atleast two attachment areas, each having the preferred geometry discussedabove.

FIGS. 17A and 17B show two preferred cross-sectional configurationswhich may be used along some or all of the length of the translationmembers and/or arms 110 a, 110 b, 114 a, 114 b, 122 a, 122 b, 124 a, 124b. The shape is defined by a relatively broad and flat or slightlycurved outer surface 182. It is intended that when in use the outersurface faces away from the interior of the lens system and/or towardthe capsular bag 58. The remaining surfaces, proportions and dimensionsmaking up the cross-sectional shape can vary widely but mayadvantageously be selected to facilitate manufacture of the lens system100 via molding or casting techniques while minimizing stresses in thearms during use of the lens system.

FIGS. 17.C-17L depict a number of alternative cross-sectionalconfigurations which are suitable for the translation members and/orarms 110 a, 110 b, 114 a, 114 b, 122 a, 122 b, 124 a, 124 b. As shown, awide variety of cross-sectional shapes may be used, but preferably anyshape includes the relatively broad and flat or slightly curved outersurface 182.

It is further contemplated that the dimensions, shapes, and/orproportions of the cross-sectional configuration of the translationmembers and/or arms 110 a, 110 b, 114 a, 114 b, 122 a, 122 b, 124 a, 124b may vary along the length of the members/arms. This may be done inorder to, for example, add strength to high-stress regions of the arms,fine-tune their spring characteristics, add rigidity or flexibility,etc.

As discussed above, each of the anterior viewing element 106 and theposterior viewing element 118 preferably comprises an optic havingrefractive power. In one preferred embodiment, the anterior viewingelement 106 comprises a biconvex lens having positive refractive powerand the posterior viewing element 118 comprises a convexo-concave lenshaving negative refractive power. The anterior viewing element 106 maycomprise a lens having a positive power advantageously less than 55diopters, preferably less than 40 diopters, more preferably less than 35diopters, and most preferably less than 30 diopters. The posteriorviewing element 118 may comprise a lens having a power which isadvantageously between −25 and 0 diopters, and preferably between −25and −15 diopters. In other embodiments, the posterior viewing element118 comprises a lens having a power which is between −15 and 0 diopters,preferably between −13 and −2 diopters, and most preferably between −10and −5 diopters. Advantageously, the total power of the optic(s)employed in the lens system 100 is about 5-35 diopters; preferably, thetotal power is about 10-30 diopters; most preferably, the total power isabout 15-25 diopters. (As used herein, the term “diopter” refers to lensor system power as measured when the lens system 100 has been implantedin the human eye in the usual manner.) It should be noted that ifmaterials having a high index of refraction (e.g., higher than that ofsilicone) are used, the optics may be made thinner which facilitates awider range of motion for the optics. This in turn allows the use oflower-power optics than those specified above. In addition, higher-indexmaterials allow the manufacture of a higher-power lens for a given lensthickness and thereby reduce the range of motion needed to achieve agiven range of accommodation.

Some lens powers and radii of curvature presently preferred for use withan embodiment of the lens system 100 with optic(s) having a refractiveindex of about 1.432 are as follows: a +31 diopter, biconvex lens withan anterior radius of curvature of 5.944 mm and a posterior radius ofcurvature of 5.944 mm; a +28 diopter, biconvex lens with an anteriorradius of curvature of 5.656 mm and a posterior radius of curvature of7.788 mm; a +24 diopter, biconvex lens with an anterior radius ofcurvature of 6.961 mm and a posterior radius of curvature of 8.5 mm; a−10 diopter, biconcave lens with an anterior radius of curvature of18.765 mm and a posterior radius of curvature of 18.765 mm, a −8diopter, concavo-convex lens with an anterior radius of curvature ofbetween 9 mm and 9.534 mm and a posterior radius of curvature of 40 mm,and a −5 diopter, concavo-convex lens with an anterior radius ofcurvature of between 9 mm and 9.534 mm and a posterior radius ofcurvature of 20 mm. In one embodiment, the anterior viewing elementcomprises the +31 diopter lens described above and the posterior viewingelement comprises the −10 diopter lens described above. In anotherembodiment, the anterior viewing element comprises the +28 diopter lensdescribed above and the posterior viewing element comprises the −8diopter lens described above. In another embodiment, the anteriorviewing element comprises the +24 diopter lens described above and theposterior viewing element comprises the −5 diopter lens described above.

The combinations of lens powers and radii of curvature specified hereinadvantageously minimize image magnification. However, other designs andradii of curvature provide modified magnification when desirable.

The lenses of the anterior viewing element 106 and the posterior viewingelement 118 are relatively moveable as discussed above; advantageously,this movement is sufficient to produce an accommodation of at least onediopter, preferably at least two diopters and most preferably at leastthree diopters. In other words, the movement of the optics relative toeach other and/or to the cornea is sufficient to create a differencebetween (i) the refractive power of the user's eye in the accommodatedstate and (ii) the refractive power of the user's eye in theunaccommodated state, having a magnitude expressed in diopters asspecified above. Where the lens system 100 has a single optic, themovement of the optic relative to the cornea is sufficient to create adifference in focal power as specified above.

Advantageously, the lens system 100 can be customized for an individualpatient's needs by shaping or adjusting only one of the four lens faces,and thereby altering the overall optical characteristics of the system100. This in turn facilitates easy manufacture and maintenance of aninventory of lens systems with lens powers which will fit a largepopulation of patients, without necessitating complex adjustmentprocedures at the time of implantation. It is contemplated that all ofthe lens systems in the inventory have a standard combination of lenspowers, and that a system is fitted to a particular patient by simplyshaping only a designated “variable” lens face. This custom-shapingprocedure can be performed to-order at a central manufacturing facilityor laboratory, or by a physician consulting with an individual patient.In one embodiment, the anterior face of the anterior viewing element isthe designated sole variable lens face. In another embodiment, theanterior face of the posterior viewing element is the only variableface. However, any of the lens faces is suitable for such designation.The result is minimal inventory burden with respect to lens power (allof the lens systems in stock have the same lens powers) withoutrequiring complex adjustment for individual patients (only one of thefour lens faces is adjusted in the fitting process).

IV. The Lens System Alternative Embodiments

FIG. 17M depicts another embodiment of the lens system 100 in which theanterior viewing element 106 comprises an optic with a smaller diameterthan the posterior viewing element 118, which comprises an optic with aperipheral positive-lens portion 170 surrounding a central negativeportion 172. This arrangement enables the user of the lens system 100 tofocus on objects at infinity, by allowing the (generally parallel) lightrays incident upon the eye from an object at infinity to bypass theanterior viewing element 106. The peripheral positive-lens portion 170of the posterior viewing element 118 can then function alone inrefracting the light rays, providing the user with focused vision atinfinity (in addition to the range of visual distances facilitated bythe anterior and posterior viewing elements acting in concert). Inanother embodiment, the anterior viewing element 106 comprises an optichaving a diameter of approximately 3 millimeters or less. In yet anotherembodiment, the anterior viewing element 106 comprises an optic having adiameter of approximately 3 millimeters or less and a refractive powerof less than 55 diopters, more preferably less than 30 diopters. Instill another embodiment, the peripheral positive-lens portion 170 has arefractive power of about 20 diopters.

FIG. 17N shows an alternative arrangement in which, the anterior viewingelement 106 comprises an optic having a central portion 176 withrefractive power, and a surrounding peripheral region 174 having arefractive power of substantially zero, wherein the central region 176has a diameter smaller than the optic of the posterior viewing element118, and preferably has a diameter of less than about 3 millimeters.This embodiment also allows some incident light rays to pass theanterior viewing element (though the zero-power peripheral region 174)without refraction, allowing the peripheral positive-lens portion 170posterior viewing element 118 to function alone as described above.

FIGS. 18 and 19 depict another embodiment 250 of the intraocular lens.It is contemplated that, except as noted below, this embodiment 250 islargely similar to the embodiment disclosed in FIGS. 3-17. The lens 250features an anterior biasing element 108 and posterior biasing element120 which are arranged asymmetrically as the lens system 100 is viewedfrom the side. As used herein to describe the biasing elements 108, 120,“asymmetric” or “asymmetrically” means that, as the lens system 100 isviewed from the side, the first anterior translation member 110 and thefirst posterior translation member 122 extend from the first apex 112 atunequal first anterior and posterior biasing angles δ₁, δ₂ with respectto the line B-B (which represents the edge of a plane which issubstantially orthogonal to the optical axis and intersects the firstand second apices 112, 116) and/or that the second anterior translationmember 114 and the second posterior translation member 124 extend fromthe second apex 116 at unequal second anterior and posterior biasingangles δ₃, δ₄ with respect to the line B-B.

In the embodiment shown in FIGS. 18-19, the first and second anteriorbiasing angles δ₁, δ₃ are greater than the corresponding first andsecond posterior biasing angles δ₂, δ₄. This arrangement advantageouslymaintains the posterior viewing element 118 and apices 112, 116 in asubstantially stationary position. Consequently, the moving mass of thelens system 250 is reduced, and the anterior viewing element 106 canmove more quickly over a wider range along the optical axis under agiven motive force. (Note that even where the posterior biasing element120 and its constituent first and second posterior translation members122, 124 are substantially immobile, they are nonetheless “biasingelements” and “translation members” as those terms are used herein.) Inanother embodiment, the anterior biasing element 108 and posteriorbiasing element 120 are arranged asymmetrically in the oppositedirection, i.e. such that the first and second anterior biasing anglesδ₁, δ₃ are smaller than the corresponding first and second posteriorbiasing angles δ₂, δ₄. This arrangement also provides for a wider rangeof relative movement of the viewing elements, in comparison to a“symmetric” system.

It should be further noted that the viewing elements 106, 118 shown inFIGS. 18-19 are asymmetrically positioned in that the posterior viewingelement 118 is closer to the line B-B than is the anterior viewingelement 106. It has been found that this configuration yields desirableperformance characteristics irrespective of the configuration of thebiasing elements 108, 120. In alternative embodiments, the viewingelements 106, 118 may be positioned symmetrically with respect to theline B-B, or they may be positioned asymmetrically with the anteriorviewing element 106 closer to the line B-B than the posterior viewingelement 118 (see FIG. 4 wherein the line in question is denoted A-A).Furthermore, the symmetry or asymmetry of the biasing elements andviewing elements can be selected independently of each other.

FIG. 20 shows another embodiment 350 of an intraocular lens in which theposterior viewing element 118 comprises an annular frame member defininga void therein, while the anterior viewing element 106 comprises anoptic having refractive power. Alternatively, the posterior viewingelement 118 could comprise a zero power lens or a simple transparentmember. Likewise, in another embodiment the anterior viewing element 106could comprise an annular frame member with a void therein or a simplezero power lens or transparent member, with the posterior viewingelement 118 comprising an optic having refractive power. As a furtheralternative, one or both of the anterior and posterior viewing elements106, 118 may comprise an annular or other perimeter frame member whichcan receive a removable optic (or a “one-time install” optic) with aninterference type fit and/or subsequent adhesive or welding connections.Such a configuration facilitates assembly and/or fine-tuning of the lenssystem during an implantation procedure, as will be discussed in furtherdetail below.

V. The Lens System: Additional Features

FIG. 21 depicts the function of the distending portion 132 in greaterdetail. The lens system 100 is shown situated in the capsular bag 58 inthe customary manner with the anterior viewing element 106 and posteriorviewing element 118 arranged along the optical axis. The capsular bag 58is shown with a generally circular anterior opening 66 which may oftenbe cut into the capsular bag during installation of the lens system 100.The first and second distending members 134, 136 of the distendingportion 132 distend the capsular bag 58 so that intimate contact iscreated between the posterior face of the posterior viewing elementand/or the posterior biasing element 120. In addition, intimate contactis facilitated between the anterior face of the anterior viewing element106 and/or anterior biasing element 108. The distending members 134, 136thus remove any slack from the capsular bag 58 and ensure optimum forcecoupling between the bag 58 and the lens system 100 as the bag 58 isalternately stretched and released by the action of the ciliary muscle.

Furthermore, the distending members 134, 136 reshape the capsular bag 58into a taller, thinner configuration along its range of accommodation toprovide a wider range of relative motion of the viewing elements 106,118. When the capsular bag 58 is in the unaccommodated state, thedistending members 134, 136 force the capsular bag into a thinnerconfiguration (as measured along the optical axis) in comparison to theunaccommodated configuration of the capsular bag 58 with the naturallens in place. Preferably, the distending members 134, 136 cause thecapsular bag 58 to taken on a shape in the unaccommodated state which isabout 1.0-2.0 mm thinner, more preferably about 1.5 mm thinner, alongthe optical axis than it is with the natural lens in place and in theunaccommodated state.

With such a thin “starting point” provided by the distending members134, 136, the viewing elements 106, 118 of the lens system can move agreater distance apart, and provide a greater range of accommodation,without causing undesirable contact between the lens system and theiris. Accordingly, by reshaping the bag as discussed above thedistending members 134, 136 facilitate a range of relative motion of theanterior and posterior viewing elements 106, 118 of about 0.5-4 mm,preferably about 1-3 mm, more preferably about 1-2 mm, and mostpreferably about 1.5 mm.

The distending portion 132/distending members 134, 136 are preferablyseparate from the anterior and posterior biasing elements 108, 120; thedistending members 134, 136 thus preferably play no part in biasing theanterior and posterior viewing elements 106, 118 apart toward theaccommodated position. This arrangement is advantageous because theapices 112, 116 of the biasing elements 108, 120 reach their point ofminimum protrusion from the optical axis (and thus the biasing elementsreach their minimum potential effectiveness for radially distending thecapsular bag) when the lens system 100 is in the accommodated state (seeFIG. 16), which is precisely when the need is greatest for a tautcapsular bag so as to provide immediate response to relaxation of theciliary muscles. The preferred distending portion is “static” (asopposed to the “dynamic” biasing members 108, 120 which move whileurging the viewing elements 106, 118 to the accommodated position orcarrying the viewing elements to the unaccommodated position) in thatits member(s) protrude a substantially constant distance from theoptical axis throughout the range of motion of the viewing elements 106,118. Although some degree of flexing may be observed in the distendingmembers 134, 136, they are most effective when rigid. Furthermore, thethickness and/or cross-sectional profile of the distending members134/136 may be varied over the length of the members as desired toprovide a desired degree of rigidity thereto.

The distending portion 132/distending members 132, 134 advantageouslyreshape the capsular bag 58 by stretching the bag 58 radially away fromthe optical axis and causing the bag 58 to take on a thinner, tallershape throughout the range of accommodation by the eye. This reshapingis believed to facilitate a broad (as specified above) range of relativemotion for the viewing elements of the lens system 100, with appropriateendpoints (derived from the total system thicknesses detailed above) toavoid the need for unacceptably thick optic(s) in the lens system.

If desired, the distending members 134, 136 may also function as hapticsto stabilize and fixate the orientation of the lens system 100 withinthe capsular bag. The openings 134 c, 136 c of the preferred distendingmembers 134,136 permit cellular ingrowth from the capsular bag uponpositioning of the lens system 100 therein. Finally, othermethodologies, such as a separate capsular tension ring or the use ofadhesives to glue the capsular bag together in selected regions, may beused instead of or in addition to the distending portion 132, to reduce“slack” in the capsular bag.

A tension ring can also act as a physical barrier to cell growth on theinner surface of the capsular bag, and thus can provide additionalbenefits in limiting posterior capsule opacification, by preventingcellular growth from advancing posteriorly on the inner surface of thebag. When implanted, the tension ring firmly contacts the inner surfaceof the bag and defines a circumferential barrier against cell growth onthe inner surface from one side of the barrier to another.

FIG. 21A shows an alternative configuration of the distending portion132, in which the distending members 134, 136 comprise first and secondarcuate portions which connect at either end to the apices 112, 116 toform therewith an integral perimeter member. In this arrangement it ispreferred that the distending members and apices form an oval withheight I smaller than width J.

FIG. 21B shows another alternative configuration of the distendingportion 132, in which arcuate rim portions 137 interconnect the apices112, 116 and the free ends 134 b, 136 b of the distending members 134,136. Thus is formed an integral perimeter member with generally higherlateral rigidity than the arrangement depicted in FIG. 21A.

FIG. 21C shows another alternative configuration of the distendingportion 132, in which the distending members 134, 136 are integrallyformed with the first and second posterior translation members 122, 124.The distending members 134, 136 and translation members 122, 124 thusform common transition members 139 which connect to the periphery of theposterior viewing element 118.

FIG. 22 shows the function of the retention portion 126 in greaterdetail. It is readily seen that the first and second retention members128, 130 facilitate a broad contact base between the anterior portion ofthe lens system 100 and the anterior aspect of the capsular bag 58. Byappropriately spacing the first and second retention members 128, 130,the members prevent extrusion of the anterior viewing element 106through the anterior opening 66. It is also readily seen that wherecontact occurs between the anterior aspect of the capsular bag 58 andone or both of the retention members 128, 130, the retention membersalso participate in force coupling between the bag 58 and the lenssystem 100 as the bag is stretched and released by the action of theciliary muscles.

As best seen in FIGS. 21 and 22, the anterior portion 102 of the lenssystem 100 forms a number of regions of contact with the capsular bag58, around the perimeter of the anterior viewing element 106. In theillustrated embodiment, at least some of these regions of contact arelocated on the anteriormost portions of the anterior biasing element108, specifically at the transition members 138, 140, and at theretention members 128, 130. The transition members and the retentionmembers define spaces therebetween at the edges of the anterior viewingelement 106 to permit fluid to flow between the interior of the capsularbag 58 and the portions of the eye anterior of the bag 58. In otherwords, the anterior portion of the lens system 100 includes at least onelocation which is spaced from and out of contact with the capsular bag58 to provide a fluid flow channel extending from the region between theviewing elements 106, 118 to the exterior of the bag 58. Otherwise, ifthe anterior portion 102 of the lens system 100 seals the anterioropening 66 of the bag 58, the resulting prevention of fluid flow cancause the aqueous humor in the capsular bag to stagnate, leading to aclinically adverse event, and can inhibit the movement of the lenssystem 100 between the accommodated and unaccommodated states.

If desired, one or both of the retention members 128, 130 may have anopening 129 formed therein to permit fluid flow as discussed above. (SeeFIG. 21A.)

The retention members 128, 130 and the transition members 138, 140 alsoprevent contact between the iris and the anterior viewing element 106,by separating the anterior opening 66 from the anterior face of theviewing element 106. In other words, the retention members 128, 130 andthe transition members 138, 140 displace the anterior aspect of thecapsular bag 58, including the anterior opening 66, anteriorly from theanterior viewing element 106, and maintain this separation throughoutthe range of accommodation of the lens system. Thus, if contact occursbetween the iris and the lens system-capsular bag assembly, no part ofthe lens system will touch the iris, only the capsular bag itself, inparticular those portions of the bag 58 overlying the retention members128, 130 and/or the transition members 138, 140. The retention members128, 130 and/or the transition members 138, 140 therefore maintain aseparation between the iris and the lens system, which can be clinicallyadverse if the contacting portion(s) of the lens system are constructedfrom silicone.

As depicted in FIG. 22A, one or more stop members or separation members190 may be located where appropriate on the anterior and/or posteriorbiasing elements 108, 120 to limit the convergent motion of the anteriorand posterior viewing elements 106, 118, and preferably prevent contacttherebetween. As the lens system 100 moves toward the unaccommodatedposition, the stop member(s) located on the anterior biasing element 108come into contact with the posterior biasing element 120 (or withadditional stop member(s) located on thereon), and any stop member(s)located on the posterior biasing element 120 come into contact with theanterior biasing element 108 (or with additional stop member(s) locatedthereon). The stop members 190 thus define a point or state of maximumconvergence (in other words, the unaccommodated state) of the lenssystem 100/viewing elements 106, 118. Such definition advantageouslyassists in setting one extreme of the range of focal lengths which thelens system may take on (in those lens systems which include two or moreviewing elements having refractive power) and/or one extreme of therange of motion of the lens system 100.

The stop members 190 shown in FIG. 22A are located on the first andsecond anterior translation members 110, 114 of the anterior biasingelement 108 and extend posteriorly therefrom. When the anterior andposterior viewing elements 106, 118 move together, one or more of thestop members 190 will contact the posterior translation member(s) 122,124, thereby preventing further convergent motion of the viewingelements 106, 118. Of course, in other embodiments the stop member(s)190 can be in any suitable location on the lens system 100.

FIGS. 44-48 depict another embodiment of the lens system 100 having anumber of stop members or separation members 190. In this embodiment thestop members 190 include posts 190 a and tabs 190 b, although it will beapparent that any number or combination of suitable shapes may beemployed for the stop members 190. Each of the stop members 190 has atleast one contact surface 191, one or more of which abuts an opposingsurface of the lens system 100 when the anterior and posterior viewingelements 106, 118 converge to a minimum separation distance SD (see FIG.47). In the embodiment shown, one or more of the contact surfaces 191 ofthe posts 190 a are configured to abut an opposing surface defined by asubstantially flat anterior perimeter portion 193 of the posteriorviewing element 118, when the viewing elements 106, 118 are at theminimum separation distance SD. One or more of the contact surfaces 191of the tabs 190 b are configured to abut opposing surfaces defined bysubstantially flat anterior faces 195 of the distending members 134,136, only if the viewing elements 106, 118 are urged together beyond theminimum separation distance SD. This arrangement permits the tabs 190 bto function as secondary stop members should the posts 190 a fail tomaintain separation of the viewing elements.

In other embodiments all of the contact surfaces 191 of the posts 190 aand tabs 190 b may be configured to contact their respective opposingsurfaces when the viewing elements 106, 118 are at the minimumseparation distance SD. In still further embodiments, the contactsurfaces 191 of the tabs 190 b may be configured to contact the opposingsurfaces when the viewing elements 106, 118 are at the minimumseparation distance SD and the contact surfaces 191 of the posts 190 aconfigured to contact the opposing surfaces only if the viewing elements106, 118 are urged together beyond the minimum separation distance SD.In one embodiment, the minimum separation distance SD is about 0.1-1.0mm; in another embodiment the minimum separation distance SD is about0.5 mm.

When one of the contact surfaces abuts one of the opposing surfaces, thetwo surfaces define a contact area CA (see FIG. 48, depicting an exampleof a contact area CA defined when the contact surface 191 of a post 190a contacts an opposing surface defined by the perimeter portion 193 ofthe posterior viewing element 118). Preferably, the contact surface andopposing surface are shaped to cooperatively minimize the size of thecontact area, to prevent adhesion between the contact surface and theopposing surface, which is often a concern when one or both of thesesurfaces has an adhesive affinity for the other. In the embodimentshown, this non-adhesive characteristic is achieved by employing asubstantially hemispherical contact surface 191 and a substantially flatopposing surface (perimeter portion 193). Of course, otherconfigurations can be selected for the contact surface(s) 191, includingconical, frustoconical, hemicylindrical, pyramidal, or other rounded,tapered or pointed shapes. All of these configurations minimize thecontact area CA while permitting the cross-sectional area CS of the stopmember 190 (such as the post 190 a depicted) to be made larger than thecontact area CA, to impart sufficient strength to the stop memberdespite the relatively small contact area CA. Indeed, when constructingthe contact surface(s) 191 any configuration may be employed whichdefines a contact area CA which is smaller than the cross-sectional areaCS of the stop member 190. As further alternatives, the contactsurface(s) 191 may be substantially flat and the opposing surface(s) mayhave a shape which defines, upon contact with the opposing surface, acontact area CA which is smaller than the cross-sectional area CS of thestop member. Thus, the opposing surface(s) may have, for example, ahemispherical, conical, frustoconical, hemicylindrical, pyramidal, orother rounded, tapered or pointed shape.

Other design features of the stop members 190 can be selected tomaximize their ability to prevent adhesion of the contact surface(s) tothe corresponding opposing surface(s), or adhesion to each other of anypart of the anterior and posterior portions 102, 104 of the lens system100. For example, the contact and opposing surfaces may be formed fromdissimilar materials to reduce the effect of any self-adhesive materialsemployed in forming the lens system 100. In addition the shape and/ormaterial employed in constructing one or more of the stop members 190can be selected to impart a spring-like quality to the stop member(s) inquestion, so that when the stop member is loaded in compression as theviewing elements are urged together at the minimum separation distance,the stop member tends to exert a resisting spring force, due to eitherbending or axial compression (or both) of the stop member, which in turnderive from the elasticity of the material(s) from which the stop memberis constructed, or the shape of the stop member, or both. Thisspringlike quality is particularly effective for inhibiting adhesion ofareas of the anterior and posterior portions 102, 104 other than thecontact surface(s) and opposing surface(s).

As used herein, the term “adhesion” refers to attachment to each otherof (i) an area of the anterior portion 102 of the lens system 100 and(ii) a corresponding area of the posterior portion 104 (other than theapices 112, 116), wherein such attachment is sufficiently strong toprevent, other than momentarily, the anterior and posterior viewingelements 106, 118 from moving apart along the optical axis under thebiasing force of the anterior and/or posterior biasing elements 108,120. If the areas in question are formed of different materials,adhesion may occur where at least one of the materials has an adhesiveaffinity for the other material. If the areas in question are formed ofthe same material, adhesion may occur where the material has an adhesiveaffinity for itself.

In the embodiment shown, four posts 190 a are positioned near theperimeter of the anterior viewing element 106, equally angularly spacedaround the optical axis. In addition, two tabs 190 b are located oneither side of the anterior viewing element, midway between the apices112, 116 of the lens system. Naturally, the number, type and/or positionof the stop members 190 can be varied while preserving the advantageousfunction of maintaining separation between the anterior and posteriorportions of the lens system.

The illustrated embodiment employs stop members 190 which extendposteriorly from the anterior portion 102 of the lens system 100, sothat the contact surfaces 191 are located on the posterior extremitiesof the stop members 190 and are configured to abut opposing surfacesformed on the posterior portion 104 of the lens system 100. However, itwill be appreciated that some or all of the stop members 190 may extendanteriorly from the posterior portion 104 of the lens system 100, sothat their contact surfaces 191 are located on the anterior extremitiesof the stop members 190 and are configured to abut opposing surfacesformed on the anterior portion 102 of the lens system 100.

VI. Mold Tooling

FIGS. 23-34 depict a mold system 500 which is suitable for molding thelens system 100 depicted in FIG. 3-17. The mold system 500 generallycomprises a first mold 502, a second mold 504 and a center mold 506. Thecenter mold 506 is adapted to be positioned between the first mold 502and the second mold 504 so as to define a mold space for injectionmolding or compression molding the lens system 100. The mold system 500may be formed from suitable metals, high-impact-resistant plastics or acombination thereof, and can be produced by conventional machiningtechniques such as lathing or milling, or by laser orelectrical-discharge machining. The mold surfaces can be finished ormodified by sand blasting, etching or other texturing techniques.

The first mold 502 includes a first mold cavity 508 with a firstanterior mold face 510 surrounded by an annular trough 512 and a firstperimeter mold face 514. The first mold 502 also includes a projection516 which facilitates easier mating with the second mold 504.

The center mold 506 includes a first center mold cavity 518 whichcooperates with the first mold cavity 508 to define a mold space forforming the anterior portion 102 of the lens system 100. The firstcenter mold cavity 518 includes a central anterior mold face 520 which,upon placement of the center mold 506 in the first mold cavity 508,cooperates with the first anterior mold face 510 to define a mold spacefor the anterior viewing element 106. In so doing, the first anteriormold face 510 defines the anterior face of the anterior viewing element106 and the central anterior mold face 520 defines the posterior face ofthe anterior viewing element 106. In fluid communication with thechamber formed by the first anterior mold face 510 and the centralanterior mold face 520 are lateral channels 522, 524 (best seen in FIG.31) which form spaces for molding the first and second transitionmembers 138, 140, along with the arms 110 a, 110 b of the first anteriortranslation member 110 as well as the arms 114 a, 114 b of the secondanterior translation member 114. The first center mold cavity 518 alsoincludes retention member cavities 526, 528 which define spaces formolding the first and second retention members 128, 130 to the anteriorviewing element 106.

The second mold 504 includes a second mold cavity 530 with a secondposterior mold space 532, a generally cylindrical transition 534extending therefrom and connecting to a second perimeter mold face 536.Lateral notches 538, 540 (best seen in FIGS. 26 and 27) are formed inthe second perimeter mold face 536. The second mold 504 also includes aninput channel 542 connected to an input channel opening 544 forintroducing material into the mold system 500. Also formed in the secondmold 504 is an output channel 546 and an output channel opening 548. Agenerally cylindrical rim 550 is included for mating with the projection516 of the first mold 502.

The center mold 506 includes a second center mold cavity 552 whichcooperates with the second mold cavity 530 to define a mold space forthe posterior portion 104 of the lens system 100. The second center moldcavity 552 includes a central posterior mold face 554 which, uponplacement of the center mold 506 in engagement with the second moldcavity 530, cooperates with the second posterior mold face 532 and thetransition 534 to define a chamber for forming the posterior viewingelement 118. In fluid communication with the chamber formed by thecentral posterior mold face 554 and the second posterior mold face 532are lateral channels 556, 558, 560, 562 which provide a mold space forforming the arms 122 a, 122 b of the first posterior translation member122 and the arms 124 a, 124 b of the second posterior translation member124. The second center mold cavity 552 includes lateral projections 564,566 which coact with the notches 538, 540 formed in the second moldcavity 530. The chambers formed therebetween are in fluid communicationwith the chamber defined by the central posterior mold face 554 and thesecond posterior mold face 532 to form the first and second distendingmembers 134, 136 integrally with the posterior viewing element 118.

The center mold 506 includes a first reduced-diameter portion 568 and asecond reduced-diameter portion 570 each of which, upon assembly of themold system 500, defines a mold space for the apices 112, 116 of thelens system 100.

In use, the mold system 500 is assembled with the center mold 506positioned between the first mold 502 and the second mold 504. Onceplaced in this configuration, the mold system 500 is held together underforce by appropriate techniques, and lens material is introduced intothe mold system 500 via the input channel 542. The lens material thenfills the space defined by the first mold 502, second mold 504, and thecenter mold 506 to take on the shape of the finished lens system 100.

The mold system 500 is then disassembled, and in one embodiment the lenssystem 100 is left in position on the center mold 506 after removal ofthe first and second molds 502, 504. This technique has been found toimprove the effectiveness of any polishing/tumbling/deflashingprocedures which may be performed (see further discussion below).Whether or not these or any other additional process steps areperformed, the lens system 100 is preferably removed from the centermold 506 while maintaining the interconnection of the various componentsof the lens system 100.

In another embodiment, the lens system 100 or a portion thereof isformed by a casting or liquid-casting procedure in which one of thefirst or second molds is first filled with a liquid and the center moldis placed then into engagement with the liquid-filled mold. The exposedface of the center mold is then filled with liquid and the other of thefirst and second molds is placed into engagement with the rest of themold system. The liquid is allowed or caused to set/cure and a finishedcasting may then removed from the mold system.

The mold system 500 can advantageously be employed to produce a lenssystem 100 as a single, integral unit (in other words, as a single pieceof material). Alternatively, various portions of the lens system 100 canbe separately molded, casted, machined, etc. and subsequently assembledto create a finished lens system. Assembly can be performed as a part ofcentralized manufacturing operations; alternatively, a physician canperform some or all of the assembly before or during the implantationprocedure, to select lens powers, biasing members, system sizes, etc.which are appropriate for a particular patient.

The center mold 506 is depicted as comprising an integral unit withfirst and second center mold cavities 518, 552. Alternatively, thecenter mold 506 may have a modular configuration whereby the first andsecond mold cavities 518, 552 may be interchangeable to adapt the centermold 506 for manufacturing a lens system 100 according to a desiredprescription or specification, or to otherwise change the power(s) ofthe lenses made with the mold. In this manner the manufacture of a widevariety of prescriptions may be facilitated by a set of mold cavitieswhich can be assembled back-to-back or to opposing sides of a main moldstructure.

FIGS. 49-53 depict one embodiment of a method for manufacturing thecenter mold 506. First, a cylindrical blank 1500 formed from anymaterial (such as Ultem) suitable for use in the mold tooling, is loadedinto a holder 1502 as shown in FIG. 49. The holder 1502 has a mainchamber 1504 which has an inner diameter substantially similar to thatof the blank 1500, a smaller-diameter secondary chamber 1506 rearward ofthe main chamber 1504, and a passage 1508 located rearward of thesecondary chamber 1506 and further defined by an annulus 1510. Theholder also includes two or more holder bores 1512 which facilitateattachment of the holder 1502 to a blocker (discussed in further detailbelow). The blank is “blocked” in the holder by filling the secondarychamber 1506 and passage 1508 with water-soluble wax 1514.

Once the blank 1500 has been loaded and blocked into the holder 1502,the holder 1502 is secured to a blocker 1516 by bolts or pins (notshown) which fit snugly into the holder bores 1512. The holder bores1512 align precisely with corresponding blocker bores 1517, by virtue ofa snug fit between the blocker bores 1517 and the bolts/pins. Theblocker-holder assembly is then loaded into a conventional machine tool,such as a lathe and/or a mill, and one of the first and second centermold cavities 518, 552 (the second cavity 552 is depicted in FIG. 51) ismachined from the exposed face of the blank 1500 using conventionalmachining techniques. The holder 1502 and blank 1500, with the secondcenter mold cavity 552 formed thereon, are then removed from the blocker1516 as shown in FIG. 51.

The main chamber 1504 is then filled with water-soluble wax 1520 forwardof the second center mold cavity 552, and the wax 1514 is removed fromthe secondary chamber 1506 and the passage 1508. Next the holder 1502 isfixed to the blocker 1516 with the as-yet unmodified portion of theblank 1500 facing outward. Upon re-loading the holder-blocker assemblyinto the machine tool, a portion of the annulus 1510 is then cut away tofacilitate tool access to the blank 1500. A series of machiningoperations are then performed on the blank 1500 until the remaining moldcavity (the first center mold cavity 518 is depicted in FIG. 53) hasbeen formed. The completed center mold 506 may then be removed from theholder 1502.

The machining technique depicted in FIGS. 49-53 is advantageous in thatit facilitates fabrication of the center mold 506 (with both the firstand second center mold cavities 518, 552) from a single piece ofmaterial. While it is possible to machine the first and second centermold cavities 518, 552 from separate pieces of material which aresubsequently glued together, such assembly creates a seam in the centermold which can retain contaminants and introduce those contaminants intothe mold when forming the lens system 100. In addition, the assembly ofthe center mold 506 from two halves introduces errors wherein the firstand second center mold cavities 518, 552 may be angularly shifted withrespect to each other about the optical axis, or wherein the moldcavities 518, 552 are non-concentric (i.e., shifted with respect to eachother in a direction orthogonal to the optical axis). The methoddepicted in FIGS. 49-53 eliminates these problems by retaining the blank1500 in the holder 1502 throughout the fabrication process and byenforcing precise axial alignment, via forced alignment of the bores1512 with the blocker bores 1517, when machining of both mold cavities.

In another embodiment, the center mold 506 is formed by a moldingprocess rather than by machining. The center mold 506 may be molded fromany of the materials disclosed herein as suitable for forming the lenssystem 100 itself, including but not limited to silicone, acrylics,polymethylmethacrylate (PMMA), block copolymers ofstyrene-ethylene-butylene-styrene (C-FLEX) or other styrene-basecopolymers, polyvinyl alcohol (PVA), polyurethanes, hydrogels or anyother moldable polymers or monomers.

The lens system which is formed when employing the molded center mold506 may itself be molded from the same material as the center mold 506.For example, the center mold 506 may be molded from silicone, and thenthe lens system 100 may be molded from silicone by using the mold system500 with the molded silicone center mold 506.

The center mold 506 can be molded by any suitable conventionaltechniques. A polished, optical quality initial mold set can be used tomake center molds which in turn will produce lens systems with opticalquality surfaces on the posterior face of the anterior optic, and theanterior face of the posterior optic. Alternatively (or additionally),the molded center mold can be polished and/or tumbled to produce anoptically-accurate center mold.

The molded center mold 506 offers several advantages over a machinedcenter mold. First, it is quicker, cheaper and easier to produce thecenter mold in large quantities by molding instead of machining. This inturn facilitates leaving the lens system in position on the center mold(see FIG. 54) while the lens system is tumbled, polished and/ordeflashed, without incurring undue expense. The presence of the centermold between the optics increases the effectiveness of thetumbling/polishing/deflashing by increasing the hoop strength of thelens system, so that the energy of the impacting tumbling beads is notdissipated in macroscopic deformation of the lens system. Molding alsopermits softer materials to be employed in forming the center mold, anda softer center mold is more resistant to damage from deflashing toolsand processes, resulting in fewer center molds lost to suchprocess-related damage.

VII. Materials/Surface Treatments

Preferred materials for forming the lens system 100 include silicone,acrylics, polymethylmethacrylate (PMMA), block copolymers ofstyrene-ethylene-butylene-styrene (C-FLEX) or other styrene-basecopolymers, polyvinyl alcohol (PVA), polyurethanes, hydrogels or anyother suitable polymers or monomers. In addition, any portion of thelens system 100 other than the optic(s) may be formed from stainlesssteel or a shape-memory alloy such as nitinol or any iron-basedshape-memory alloy. Metallic components may be coated with gold toincrease biocompatibility. Where feasible, material of a lower Shore Ahardness such as 15 A may be used for the optic(s), and material ofhigher hardness such as 35 A may be used for the balance of the lenssystem 100. Finally, the optic(s) may be formed from a photosensitivesilicone to facilitate post-implantation power adjustment as taught inU.S. patent application Ser. No. 09/416,044, filed Oct. 8, 1999, titledLENSES CAPABLE OF POST-FABRICATION POWER MODIFICATION, the entirecontents of which are hereby incorporated by reference herein.

Methyl-methylacrylate monomers may also be blended with any of thenon-metallic materials discussed above, to increase the lubricity of theresulting lens system (making the lens system easier to fold or roll forinsertion, as discussed further below). The addition ofmethyl-methylacrylate monomers also increases the strength andtransparency of the lens system.

The optics and/or the balance of the lens system 100 can also be formedfrom layers of differing materials. The layers may be arranged in asimple sandwich fashion, or concentrically. In addition, the layers mayinclude a series of polymer layers, a mix of polymer and metalliclayers, or a mix of polymer and monomer layers. In particular, a nitinolribbon core with a surrounding silicone jacket may be used for anyportion of the lens system 100 except for the optics; anacrylic-over-silicone laminate may be employed for the optics. A layeredconstruction may be obtained by pressing/bonding two or more layerstogether, or deposition or coating processes may be employed.

Where desired, the anterior optic may be formed from a materialdifferent from that used to form the posterior optic. This may be doneto take advantage of differences between the respective materials inrefractive index, mechanical properties or resistance to posteriorcapsule opacification (“PCO”), or to achieve an appropriate balance ofmechanical and optical properties. Additionally, the use of differingmaterials can increase resistance to intra-lenticular opacification(“ILO”). For example, the material forming the posterior optic may beselected for its resistance to PCO, and/or for its rigidity (so as toform a relatively rigid base for the biasing action of the biasingelements 108, 120, thereby maximizing anterior displacement of theanterior biasing element). Thus, the posterior optic may be formed fromacrylic; for example, a hydrophobic acrylic. The material forming theanterior optic may be selected for its high index of refraction, to keepto a minimum the size and weight of the anterior optic (and the lenssystem as a whole), thereby maximizing the range and speed of motion ofthe anterior optic in response to a given biasing force. To achievethese properties the anterior optic may be formed from silicone; forexample, high-refractive-index silicones (generally, silicones with arefractive index greater than about 1.43, or silicones with a refractiveindex of about 1.46).

In other embodiments, the anterior optic may be formed from any suitablematerial (including those disclosed herein), and the posterior optic maybe formed from any suitable material (including those disclosed herein)other than the material chosen to form the anterior optic. In oneembodiment the anterior optic is formed from silicone and the posterioroptic is formed from acrylic; in another embodiment the anterior opticis formed from acrylic and the posterior optic is formed from silicone.

The optics may be considered to be formed from different polymericmaterials where no more than about 10 mole percent of recurring units ofthe polymer employed in the anterior optic are the same as the primaryrecurring units of the polymer employed in the posterior optic; and/orwhere no more than about 10 mole percent of recurring units of thepolymer employed in the posterior optic are the same as the primaryrecurring units of the polymer employed in the anterior optic. Ingeneral, these conditions are desirable in order for the two materialsto have sufficiently different material properties. As used herein, a“primary” recurring unit of a given polymer is the recurring unit whichis present in such polymer in the greatest quantity by mole percentage.

In another embodiment, the optics may be considered to be formed fromdifferent polymeric materials where no more than about 10 mole percentof recurring units of the polymer employed in the anterior optic are ofthe same type as the primary recurring units of the polymer employed inthe posterior optic; and/or where no more than about 10 mole percent ofthe recurring units of the polymer employed in the posterior optic areof the same type as the primary recurring units of the polymer employedin the anterior optic. As used herein, recurring units of the same“type” are in the same chemical family (i.e., having the same or similarfunctionality) or where the backbone of the polymers formed by suchrecurring units is essentially the same.

In one embodiment, portions of the lens system 100 other than theoptic(s) are formed from a shape-memory alloy. This embodiment takesadvantage of the exceptional mechanical properties of shape-memoryalloys and provides fast, consistent, highly responsive movement of theoptic(s) within the capsular bag while minimizing material fatigue inthe lens system 100. In one embodiment, one or both of the biasingelements 108, 120 are formed from a shape-memory alloy such as nitinolor any iron-based shape-memory alloy. Due to the flat stress-straincurve of nitinol, such biasing elements provide a highly consistentaccommodation force over a wide range of displacement. Furthermore,biasing elements formed from a shape-memory alloy, especially nitinol,retain their spring properties when exposed to heat (as occurs uponimplantation into a human eye) while polymeric biasing elements tend tolose their spring properties, thus detracting from the responsiveness ofthe lens system. For similar reasons, it is advantageous to useshape-memory alloys such as those discussed above in forming any portionof a conventional (non-accommodating) intraocular lens, other than theoptic.

Where desired, various coatings are suitable for components of the lenssystem 100. A heparin coating may be applied to appropriate locations onthe lens system 100 to prevent inflammatory cell attachment (ICA) and/orposterior capsule opacification (PCO); naturally, possible locations forsuch a coating include the posterior biasing element 120 and theposterior face of the posterior viewing element 118. Coatings can alsobe applied to the lens system 100 to improve biocompatibility; suchcoatings include “active” coatings like P-15 peptides or RGD peptides,and “passive” coatings such as heparin and other mucopolysaccharides,collagen, fibronectin and laminin. Other coatings, including hirudin,teflon, teflon-like coatings, PVDF, fluorinated polymers, and othercoatings which are inert relative to the capsular bag may be employed toincrease lubricity at locations (such as the optics and distendingmembers) on the lens system which contact the bag, or Hema or siliconecan be used to impart hydrophilic or hydrophobic properties to the lenssystem 100.

It is also desirable subject the lens system 100 and/or the moldsurfaces to a surface passivation process to improve biocompatibility.This may be done via conventional techniques such as chemical etching orplasma treatment.

Furthermore, appropriate surfaces (such as the outer edges/surfaces ofthe viewing elements, biasing elements, distending members, retentionmembers, etc.) of the lens system 100 can be textured or roughened toimprove adhesion to the capsular bag. This may be accomplished by usingconventional procedures such as plasma treatment, etching, dipping,vapor deposition, mold surface modification, etc. As a further means ofpreventing ICA/PCO, a posteriorly-extending perimeter wall (not shown)may be added to the posterior viewing element 118 so as to surround theposterior face of the posterior optic. The wall firmly engages theposterior aspect of the capsular bag and acts as a physical barrier tothe progress of cellular ingrowth occurring on the interior surface ofthe capsular bag. Finally, the relatively thick cross-section of thepreferred anterior viewing element 118 (see FIGS. 9, 10) ensures that itwill firmly abut the posterior capsule with no localized flexing. Thus,with its relatively sharp rim, the posterior face of the preferredposterior viewing element 118 can itself serve as a barrier to cellularingrowth and ICA/PCO. In order to achieve this effect, the posteriorviewing element 118 is preferably made thicker than conventionalintraocular lenses. As an alternative or supplement to a thick posteriorviewing element, cell growth may be inhibited by forming a pronounced,posteriorly-extending perimeter rim on the posterior face of theposterior viewing element 118. Upon implantation of the lens system 100,the rim firmly abuts the inner surface of the capsular bag 58 and actsas a physical barrier to cell growth between the posterior face of theposterior viewing element 118 and the capsular bag 58.

The selected material and lens configuration should be able to withstandsecondary operations after molding/casting such as polishing, cleaningand sterilization processes involving the use of an autoclave, orethylene oxide or radiation. After the mold is opened, the lens shouldundergo deflashing, polishing and cleaning operations, which typicallyinvolve a chemical or mechanical process, or a combination thereof.Suitable mechanical processes include tumbling, shaking and vibration; atumbling process may involve the use of a barrel with varying grades ofglass beads, fluids such as alcohol or water and polishing compoundssuch as aluminum oxides. Process rates are material dependent; forexample, a tumbling process for silicone should utilize a 6″ diameterbarrel moving at 30-100 RPM. It is contemplated that several differentsteps of polishing and cleaning may be employed before the final surfacequality is achieved.

In one embodiment, the lens system 100 is held in a fixture to provideincreased separation between, and improved process effect on, theanterior and posterior viewing elements during thedeflashing/polishing/cleaning operations. In another embodiment, thelens system 100 is everted or turned “inside-out” so that the innerfaces of the viewing elements are better exposed during a portion of thedeflashing/polishing/cleaning. FIG. 34A shows a number of expansiongrooves 192 which may be formed in the underside of the apices 112, 116of the lens system 100 to facilitate eversion of the lens system 100without damaging or tearing the apices or the anterior/posterior biasingelements 108, 120. For the same reasons similar expansion grooves may beformed on the opposite sides (i.e., the outer surfaces) of the apices112, 116 instead of or in addition to the location of grooves on theunderside.

A curing process may also be desirable in manufacturing the lens system100. If the lens system is produced from silicone entirely at roomtemperature, the curing time can be as long as several days. If the moldis maintained at about 50 degrees C., the curing time is reduced toabout 24 hours; if the mold is preheated to 100-200 degrees C. thecuring time can be as short as about 3-15 minutes. Of course, thetime-temperature combinations vary for other materials.

VIII. Multiple-Piece and Other Embodiments

FIG. 35 is a schematic view of a two-piece embodiment 600 of the lenssystem. In this embodiment the anterior portion 102 and the posteriorportion 104 are formed as separate pieces which are intended forseparate insertion into the capsular bag and subsequent assemblytherein. In one embodiment, each of the anterior and posterior portions102, 104 is rolled or folded before insertion into the capsular bag.(The insertion procedure is discussed in further detail below.) Theanterior portion 102 and posterior portion 104 are representedschematically as they may generally comprise any anterior-portion orposterior-portion structure disclosed herein; for example, they maysimply comprise the lens system 100 shown in FIGS. 3-17, bisected alongthe line/plane A-A shown in FIG. 4. The anterior portion 102 andposterior portion 104 of the two-piece lens system 600 will includefirst and second abutments 602, 604 which are intended to be placed inabutting relation (thus forming the first and second apices of the lenssystem) during the assembly procedure. The first and second abutments602, 604 may include engagement members (not shown), such as matchingprojections and recesses, to facilitate alignment and assembly of theanterior and posterior portions 102, 104.

As a further alternative, the anterior and posterior portions 102, 104of the lens system 600 may be hingedly connected at one of the abutments602, 604 and unconnected at the other, to allow sequential (butnonetheless partially assembled) insertion of the portions 102, 104 intothe capsular bag. The individual portions may be separately rolled orfolded before insertion. The two portions 102, 104 are “swung” togetherand joined at the unconnected abutment to form the finished lens systemafter both portions have been inserted and allowed to unfold/unroll asneeded.

FIG. 36 depicts schematically another embodiment 700 of a two-piece lenssystem. The lens system 700 is desirably similar to the lens system 600shown in FIG. 35, except for the formation of relatively larger, curledabutments 702, 704 which are assembled to form the apices 112, 116 ofthe system 700.

FIGS. 37 and 38 show a further embodiment 800 of the lens system, inwhich the anterior and posterior biasing elements 108, 120 compriseintegral “band” like members forming, respectively, the first and secondanterior translation members 110, 114 and the first and second posteriortranslation members 122, 124. The biasing elements 108, 120 also formreduced-width portions 802, 804 which meet at the apices of the lenssystem 800 and provide regions of high flexibility to facilitatesufficient accommodative movement. The depicted distending portion 132includes three pairs of distending members 134, 136 which have a curvedconfiguration but nonetheless project generally away from the opticalaxis.

FIGS. 38A and 38B depict another embodiment 900 of the lens system, asimplanted in the capsular bag 58. The embodiment shown in FIGS. 38A and38B may be similar to any of the embodiments described above, exceptthat the biasing elements 108, 120 are dimensioned so that the apices112, 116 abut the zonules 62 and ciliary muscles 60 when in theunaccommodated state as seen in FIG. 38A. In addition, the lens system900 is configured such that it will remain in the unaccommodated statein the absence of external forces. Thus, when the ciliary muscles 60contract, the muscles 60 push the apices 112, 116 closer together,causing the biasing elements 108, 120 to bow out and the viewingelements 106, 118 to separate and attain the accommodated state as shownin FIG. 38B. When the ciliary muscles 60 relax and reduce/eliminate theforce applied to the apices 112, 116 the biasing elements 108, 120 movethe lens system 900 to the unaccommodated state depicted in FIG. 38A.

FIGS. 38C and 38D depict biasers 1000 which may be used bias the lenssystem 100 toward the accommodated or unaccommodated state, depending onthe desired operating characteristics of the lens system. It istherefore contemplated that the biasers 1000 may be used with any of theembodiments of the lens system 100 disclosed herein. The bias providedby the biasers 1000 may be employed instead of, or in addition to, anybias generated by the biasing elements 108, 120. In one embodiment (seeFIG. 38C), the biasers 1000 may comprise U-shaped spring members havingapices 1002 located adjacent the apices 112, 116 of the lens system 100.In another embodiment (see FIG. 38D), the biasers 1000 may comprise anysuitable longitudinal-compression springs which span the apices 112, 116and interconnect the anterior and posterior biasing elements 108, 120.By appropriately selecting the spring constants and dimensions of thebiasers 1000 (in the case of U-shaped springs, the apex angle and armlength; in the case of longitudinal-compression springs, their overalllength), the biasers 1000 can impart to the lens system 100 a biastoward the accommodated or unaccommodated state as desired.

The biasers 1000 may be formed from any of the materials disclosedherein as suitable for constructing the lens system 100 itself. Thematerial(s) selected for the biasers 1000 may be the same as, ordifferent from, the material(s) which are used to form the remainder ofthe particular lens system 100 to which the biasers 1000 are connected.The number of biasers 1000 used in a particular lens system 100 may beequal to or less than the number of apices formed by the biasingelements of the lens system 100.

FIG. 38E depicts a further embodiment of the lens system 100 in whichthe anterior translation members 110 and the posterior translationmembers 120 are paired in a number (in the example depicted, four) ofseparate positioners 1400 which are radially spaced, preferably equallyradially spaced, about the optical axis. In the depicted embodiment, theanterior and posterior translation members 110, 120 connect directly tothe periphery of the viewing elements 106, 118; however, in otherembodiments any of the connection techniques disclosed herein may beemployed. As shown, the anterior translation members 100 preferablyextend anteriorly from the periphery of the anterior viewing elementbefore bending and extending posteriorly toward the apex/apices 112. Asdiscussed above, this configuration is advantageous for promotion offluid flow through an opening formed in the anterior aspect of thecapsular bag 58. It has been found that the lens configuration shown inFIG. 38E is well suited for the folding technique shown in FIGS. 40A and40B below. In additional embodiments, the lens system 100 shown in FIG.38E may incorporate any other suitable features of the other embodimentsof the lens system 100 disclosed herein, such as but not limited to thedistending members and/or retention members detailed above.

IX. Implantation Methods

Various techniques may be employed in implanting the various embodimentsof the lens system in the eye of a patient. The physician can firstaccess the anterior aspect of the capsular bag 58 via any appropriatetechnique. Next, the physician incises the anterior of the bag; this mayinvolve making the circular opening 66 shown in FIGS. 21 and 22, or thephysician may make a “dumbbell” shaped incision by forming two smallcircular incisions or openings and connecting them with a third,straight-line incision. The natural lens is then removed from thecapsular bag via any of various known techniques, such asphacoemulsification, cryogenic and/or radiative methods. To inhibitfurther cell growth, it is desirable to remove or kill all remainingepithelial cells. This can be achieved via cryogenic and/or radiativetechniques, antimetabolites, chemical and osmotic agents. It is alsopossible to administer agents such as P15 to limit cell growth bysequestering the cells.

In the next step, the physician implants the lens system into thecapsular bag. Where the lens system comprises separate anterior andposterior portions, the physician first folds or rolls the posteriorportion and places it in the capsular bag through the anterior opening.After allowing the posterior portion to unroll/unfold, the physicianadjusts the positioning of the posterior portion until it is withinsatisfactory limits. Next the physician rolls/folds and implants theanterior portion in a similar manner, and aligns and assembles theanterior portion to the posterior portion as needed, by causingengagement of mating portions, etc. formed on the anterior and posteriorportions.

Where the lens system comprises anterior and posterior portions whichare partially assembled or partially integral (see discussion above inthe section titled MULTIPLE-PIECE AND OTHER EMBODIMENTS), the physicianemploys appropriate implantation procedures, subsequentlyfolding/rolling and inserting those portions of the lens system that areseparately foldable/rollable. In one embodiment, the physician firstrolls/folds one portion of the partially assembled lens system and theninserts that portion. The physician then rolls/folds another portion ofthe partially assembled lens system and the inserts that portion. Thisis repeated until the entire system is inside the capsular bag,whereupon the physician completes the assembly of the portions andaligns the lens system as needed. In another embodiment, the physicianfirst rolls/folds all of the separately rollable/foldable portions ofthe partially assembled lens system and then inserts the rolled/foldedsystem into the capsular bag. Once the lens system is in the capsularbag, the physician completes the assembly of the portions and aligns thelens system as needed.

It is contemplated that conventional intraocular lens folding devices,injectors, syringes and/or shooters can be used to insert any of thelens systems disclosed herein. A preferred folding/rolling technique isdepicted in FIGS. 39A-39B, where the lens system 100 is shown first inits normal condition (A). The anterior and posterior viewing elements106, 118 are manipulated to place the lens system 100 in a low-profilecondition (B), in which the viewing elements 106, 118 are out of axialalignment and are preferably situated so that no portion of the anteriorviewing element 106 overlaps any portion of the posterior viewingelement 118, as viewed along the optical axis. In the low-profileposition (B), the thickness of the lens system 100 is minimized becausethe viewing elements 106, 118 are not “stacked” on top of each other,but instead have a side-by-side configuration. From the low-profilecondition (B) the viewing elements 106, 118 and/or other portions of thelens system 100 can be folded or rolled generally about the transverseaxis, or an axis parallel thereto. Alternatively, the lens system couldbe folded or rolled about the lateral axis or an axis parallel thereto.Upon folding/rolling, the lens system 100 is placed in a standardinsertion tool as discussed above and is inserted into the eye.

When the lens system 100 is in the low-profile condition (B), the systemmay be temporarily held in that condition by the use of dissolvablesutures, or a simple clip which is detachable or manufactured from adissolvable material. The sutures or clip hold the lens system in thelow-profile condition during insertion and for a desired time afterinsertion. By temporarily holding the lens system in the low-profilecondition after insertion, the sutures or clip provide time for fibrinformation on the edges of the lens system which, after the lens systemdeparts from the low-profile condition, may advantageously bind the lenssystem to the inner surface of the capsular bag.

The physician next performs any adjustment steps which are facilitatedby the particular lens system being implanted. Where the lens system isconfigured to receive the optic(s) in “open” frame members, thephysician first observes/measures/determines the post-implantation shapetaken on by the capsular bag and lens system in the accommodated and/orunaccommodated states and select(s) the optics which will provide theproper lens-system performance in light of the observed shapecharacteristics and/or available information on the patient's opticaldisorder. The physician then installs the optic(s) in the respectiveframe member(s); the installation takes place either in the capsular bagitself or upon temporary removal of the needed portion(s) of the lenssystem from the bag. If any portion is removed, a final installation andassembly is then performed with the optic(s) in place in the framemember(s).

Where the optic(s) is/are formed from an appropriate photosensitivesilicone as discussed above, the physician illuminates the optic(s)(either anterior or posterior or both) with an energy source such as alaser until they attain the needed physical dimensions or refractiveindex. The physician may perform an intervening step ofobserving/measuring/determining the post-implantation shape taken on bythe capsular bag and lens system in the accommodated and/orunaccommodated states, before determining any needed changes in thephysical dimensions or refractive index of the optic(s) in question.

FIG. 40 depicts a technique which may be employed during lensimplantation to create a fluid flow path between the interior of thecapsular bag 58 and the region of the eye anterior of the capsular bag58. The physician forms a number of fluid-flow openings 68 in theanterior aspect of the capsular bag 58, at any desired location aroundthe anterior opening 66. The fluid-flow openings 68 ensure that thedesired flow path exists, even if a seal is created between the anterioropening 66 and a viewing element of the lens system.

Where an accommodating lens system is implanted, the openings 68 createa fluid flow path from the region between the viewing elements of theimplanted lens system, and the region of the eye anterior of thecapsular bag 58. However, the technique is equally useful for use withconventional (non-accommodating) intraocular lenses.

FIGS. 40A and 40B illustrate another embodiment of a method of foldingthe lens system 100. In this method the anterior viewing element 106 isrotated approximately 90 degrees about the optical axis with respect tothe posterior viewing element 118. This rotation may be accomplished byapplying rotational force to the upper edge of the first transitionmember 138 and the lower edge of the second transition member 140 (orvice versa), as indicated by the dots and arrows in FIG. 40A, whileholding the posterior viewing element 118 stationary, preferably bygripping or clamping the distending members 134, 136. Alternatively,rotational force may be applied in a similar manner to a right edge ofone of the retention members 128, 130 and to a left edge of the other ofthe retention members while holding the posterior viewing element 118stationary. As still further alternatives, the anterior viewing element106 could be held stationary while rotational force is applied to theposterior viewing element 118, at an upper edge of one of the distendingmembers 134, 136 and at a lower edge of the other of the distendingmembers; or both the anterior and posterior viewing elements 106, 118could be rotated with respect to each other.

Preferably, the viewing elements 106, 118 are spread apart somewhat asthe rotation is applied to the lens system so that the translationmembers and apices are drawn into the space between the viewing elements106, 118 in response to the rotational force. Once the anterior viewingelement 106 has been rotated approximately 90 degrees about the opticalaxis with respect to the posterior viewing element 118, the lens system100 takes on the configuration shown in FIG. 40B, with the retentionmembers 128, 130 generally radially aligned with the distending members134, 136 and the translation members and apices disposed between theviewing elements 106, 118. This configuration is advantageous forinserting the lens system 100 into the capsular bag 58 because itreduces the insertion profile of the lens system 100 while storing alarge amount of potential energy in the translation members. From thefolded configuration the translation members thus exert a high “rebound”force when the lens system has been inserted to the capsular bag 58,causing the lens system to overcome any self-adhesion and spring back tothe unfolded configuration shown in FIG. 40A without need for additionalmanipulation by the physician.

Once the lens system 100 is in the folded configuration shown in FIG.40B, it may be further folded and/or inserted into the capsular bag 58by any suitable methods presently known in the art or hereafterdeveloped. For example, as shown in FIG. 40C the folding method mayfurther comprise inserting the folded lens system 100 between the prongs1202, 1204 of a clip 1200, preferably with the prongs 1202, 1204oriented to extend along the transition members 138, 140, or along theretention members 128, 130 and the distending members 134, 136.

FIGS. 40D-40F illustrate the use of jaws 1250, 1252 of a pliers orforceps to fold the lens system 100 as it is held in the clip 1200.(FIGS. 40D-40F show an end view of the clip-lens system assembly withthe jaws 1250, 1252 shown in section for clarity.) As shown in FIGS. 40Dand 40E, the edges of the jaws 1250, 1252 are urged against one of theanterior and posterior viewing elements 106, 118 while the jaws 1250,1252 straddle the prong 1202 of the clip 1200. The resulting three-pointload on the lens system 1200 causes it to fold in half as shown in FIG.40E. As the lens system 100 approaches the folded configuration shown inFIG. 40F, the jaws 1250, 1252 slide into a pincer orientation withrespect to the lens system 100, characterized by contact between theinner faces 1254, 1256 of the jaws 1250, 1252 and the anterior viewingelement 106 or posterior viewing element 118. With such a pincerorientation established, the forceps may be used to grip and compressthe lens system with inward-directed pressure and the clip 1200 can bewithdrawn, as shown in FIG. 40F. With the lens system 100 thus folded,it can be inserted to the capsular bag 58 by any suitable methodpresently known in the art or hereafter developed.

FIG. 40G depicts a folding tool 1300 which may be employed to fold thelens system 100 as discussed above in connection with FIGS. 40A and 40B.The tool 1300 includes a base 1302 with brackets 1304 which hold thelens system 100 to the base 1302 by gripping the distending members 134,136. Formed within the base 1302 are arcuate guides 1306. The toolfurther comprises a rotor 1308 which in turn comprises a horizontal rod1310 and integrally formed vertical rods 1312. The vertical rods 1312engage the arcuate guides 1306, both of which have a geometric center onthe optical axis of the lens system 100. The vertical rods 1312 and thearcuate guides 1306 thus coact to allow the horizontal rod to rotate atleast 90 degrees about the optical axis of the lens system 100. Thehorizontal rod 1310 is fixed with respect to the anterior viewingelement 106 of the lens system 100 so as to prevent substantially norelative angular movement between the rod 1310 and the anterior viewingelement 106 as the rod 1310 (and, in turn, the anterior viewing element106) rotates about the optical axis of the lens system 100. This fixedrelationship may be established by adhesives and/or projections (notshown) which extend downward from the horizontal rod 1308 and bearagainst the upper edge of one of the transition members 138, 140 andagainst the lower edge of the other of the transition members as shownin FIG. 40A. As an alternative or as a supplement to this arrangement,the projections may bear against the retention members 128, 130 in asimilar manner as discussed above.

Thus, when the rotor 1308 is advanced through its range of angularmotion about the optical axis of the lens system 100, it forces theanterior viewing element 106 to rotate in concert therewith about theoptical axis, folding the lens system as discussed above in connectionwith FIGS. 40A and 40B. It is further contemplated that the folding tool1300 may comprise the lower half of a package in which the lens systemis stored and/or shipped to a customer, to minimize the labor involvedin folding the lens system at the point of use. Preferably, the lenssystem is stored in the tool 1300 in the unfolded configuration, so asto avoid undesirable deformation of the lens system.

X. Thin Optic Configurations

In some circumstances it is advantageous to make one or more of theoptics of the lens system relatively thin, in order to facilitaterolling or folding, or to reduce the overall size or mass of the lenssystem. Discussed below are various optic configurations whichfacilitate a thinner profile for the optic; any one of theseconfigurations may be employed as well as any suitable combination oftwo or more of the disclosed configurations.

One suitable technique is to employ a material having a relatively highindex of refraction to construct one or more of the optics. In oneembodiment, the optic material has an index of refraction higher thanthat of silicone. In another embodiment, the material has an index ofrefraction higher than about 1.43. In further embodiments, the opticmaterial has an index of refraction of about 1.46, 1.49 or 1.55. Instill further embodiments, the optic material has an index of refractionof about 1.43 to 1.55. By employing a material with a relatively highindex of refraction, the curvature of the optic can be reduced (in otherwords, the radius/radii of curvature can be increased) thereby reducingthe thickness of the optic without loss of focal power.

A thinner optic can also be facilitated by forming one or more of thesurfaces of one or more of the optics as an aspheric surface, whilemaintaining the focal power of the optic. As shown in FIG. 41, anaspheric, convex optic surface 1100 can be formed with the same radiusof curvature (as a comparable-power spherical surface) at the vertex1102 of the surface 1100 and a longer radius of curvature (with a commoncenter point) at its periphery 1104, creating a thinner optic withoutsacrificing focal power. This contrasts with a spherical optic surface1106, which is thicker at its vertex 1108 than is the aspheric surface1102. In one embodiment, the thickness of the optic is reduced by about19% at the vertex relative to a comparable-power spherical optic. It iscontemplated that thinner, aspheric concave optic surfaces may be usedas well. A further advantage of an aspheric optic surface is that itprovides better image quality with fewer aberrations, and facilitates athinner optic, than a comparable spherical surface.

FIG. 42 depicts a further strategy for providing a thinner optic 1150.The optic 1150 has a curved (spherical or aspheric) optic surface 1152and a flat or planar (or otherwise less curved than a comparablerefractive surface) diffractive optic surface 1154 in place of a secondcurved surface 1156. The diffractive optic surface 1154 can comprise anysuitable diffraction grating, including the grooved surface depicted orany other diffractive surface presently known or hereafter developed,including holographic optical elements. By appropriately configuring thediffractive surface 1154 as is well known in the art, the optic 1150 canbe made thinner than one having both curved surfaces 1152, 1154, whileproviding the same focal power. The use of the diffractive surface 1154not only facilitates a thinner optic, but also reduces aberrations inthe resulting image.

A further alternative for facilitating a thin, easy-to-fold optic is toemploy, in place of a biconvex optic of refractive index greater thanaqueous humor (i.e., greater than about 1.336), a biconcave optic ofrefractive index less than about 1.336, which is thinner at the opticalaxis than the biconvex optic. By constructing the biconcave optic ofmaterial having a refractive index less than about 1.336, the biconcaveoptic can be made to have the same effective focal power, when immersedin aqueous humor, as a given biconvex optic.

Still another alternative thin optic, shown in FIG. 43, is a biconcaveoptic 1160 of low refractive index (for example, about 1.40 or less orabout 1.336 or less) which is clad with first and second claddingportions 1162, 1164 constructed of higher-index material (for example,about 1.43 or greater). Such an optic can be made to have the sameeffective focal power, when immersed in aqueous humor, as a thickerbiconvex optic.

As a further alternative, one or more of the surfaces of the optics maybe formed as a multifocal surface, with spherical and/or aspheric focalregions. A multifocal surface can be made with less curvature than acomparable-power single-focus surface and thus allows the optic to bemade thinner. The additional foci provide added power which replaces orexceeds the power that is “lost” when the surface is reduced incurvature. In one embodiment, the multifocal optic is constructed as aconcentric-ring, refractive optic. In another embodiment, the multifocaloptic is implemented as a diffractive multifocal optic.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. Thus, it is intended that the scope of the present inventionherein disclosed should not be limited by the particular disclosedembodiments described above, but should be determined only by a fairreading of the claims that follow.

1. An accommodating intraocular lens for implantation in an eye, theintraocular lens having an optical axis, said lens comprising: ananterior portion including an anterior optic; and a posterior portionincluding a posterior optic having refractive power; said anteriorportion further comprising an anterior biasing element connected to saidanterior optic; said posterior portion further comprising a posteriorbiasing element connected to said posterior optic; said anterior opticbeing mounted to move relative to said posterior optic along saidoptical axis between an accommodated position and an unaccommodatedposition in response to forces within the eye, said relative movementcorresponding to a change in the combined power of the intraocular lens;wherein said anterior optic and said posterior optic are positionedfurther apart when said anterior optic is in the accommodated positionthan when said anterior optic is in the unaccommodated position, andsaid anterior optic is biased toward said accommodated position inabsence of external forces and wherein at least one of the anterioroptic and the posterior optic includes an aspheric surface.
 2. Theaccommodating intraocular lens of claim 1, wherein the anterior portionand said posterior portion being connected together by a continuousstructure that extends from the anterior portion to the posteriorportion for implantation in the eye.
 3. The accommodating intraocularlens of claim 1, the continuous structure spaced apart from the anterioror the posterior optic by a gap.